Skin Lesions and Assessment

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Where can melanoma originate?

Skin

Mouth

Anogenital mucosa

All of the above (correct)

Melanoma is the most deadly of all skin cancers.

True

What are the ABCDEs of melanoma?

Asymmetry, Irregular borders, Variegated color, Increasing diameter, Evolution

Familial cases of melanoma are associated with germline mutations affecting _____ genes.

cell cycle control Signup and view all the answers

What type of growth phase does melanoma typically have?

Both A and B Signup and view all the answers

Seborrheic keratosis is most frequently observed in which age group?

Middle-aged or older individuals Signup and view all the answers

What is actinic keratosis often associated with?

Sun exposure Signup and view all the answers

What usually indicates invasive squamous cell carcinoma is discovered?

When it is small and resectable Signup and view all the answers

Which carcinoma is the most common invasive cancer in humans?

Basal Cell Carcinoma Signup and view all the answers

Erythema multiforme is typically a hypersensitivity reaction.

True Signup and view all the answers

What do open comedones in acne vulgaris resemble?

Blackheads Signup and view all the answers

Match the following types of psoriasis with their characteristics:

Plaque Psoriasis = Sharp red scaly patches with silvery sheen Scalp Psoriasis = Raised red or silver scaly plaques on the scalp Nail Psoriasis = Dimpling resembling a golf ball Guttate Psoriasis = Small scaly lesions scattered across the body Inverse Psoriasis = Red smooth lesions in skin folds Erythrodermic Psoriasis = Lobster-like redness from head to toe Pustular Psoriasis = Characterized by pus-filled bumps Signup and view all the answers

What is a primary lesion?

An original appearance of a skin lesion Signup and view all the answers

Which of the following statements about secondary lesions is true?

They are modified by time or external agents. Signup and view all the answers

What is excoriation?

A traumatic lesion that breaks the epidermis causing a raw linear defect. Signup and view all the answers

What is lichenification?

Thickened, rough skin resulting from repeated rubbing. Signup and view all the answers

What are macules and patches?

Circumscribed, flat lesions distinguished from surrounding skin by color. Signup and view all the answers

What is onycholysis?

Separation of the nail plate from the nail bed. Signup and view all the answers

Pustules are discrete, pus-filled, raised lesions.

True Signup and view all the answers

What is the purpose of tissue repair?

Restoration of tissue architecture and functions after an injury. Signup and view all the answers

What defines regeneration in tissue repair?

The ability of tissues to replace damaged components Signup and view all the answers

Which of the following is a risk factor for venous leg ulcers?

Chronic venous hypertension Signup and view all the answers

Pressure sores are caused by prolonged compression of tissues against a bone.

True Signup and view all the answers

What defines a keloid?

Scar tissue that grows beyond the boundaries of the original wound Signup and view all the answers

What is heat exhaustion?

A condition resulting from the failure of the cardiovascular system to compensate for hypovolemia. Signup and view all the answers

What is significant about heat stroke?

Thermoregulation mechanisms fail and body temperature rises Signup and view all the answers

What is a melanocytic nevus?

A common benign neoplasm caused by activating mutations in the RAS signaling pathway. Signup and view all the answers

What is dysplastic nevus?

A type of nevus that can be a precursor to melanoma. Signup and view all the answers

What characterizes melanoma?

A common neoplasm that can be cured if detected early. Signup and view all the answers

What is the 5-year survival rate for children diagnosed with Acute Lymphoblastic Leukemia (ALL)?

85% Signup and view all the answers

What laboratory findings are associated with leukopenia in Acute Lymphoblastic Leukemia?

Joint swelling Signup and view all the answers

Children may refuse to walk due to symptoms related to Acute Lymphoblastic Leukemia.

True Signup and view all the answers

Which of the following is a category of Burkitt lymphoma?

Sporadic (nonendemic) Burkitt lymphoma Signup and view all the answers

What gene translocation is associated with all forms of Burkitt lymphoma?

MYC gene on chromosome 8 Signup and view all the answers

Burkitt lymphoma primarily affects older adults.

False Signup and view all the answers

What are Bence Jones proteins related to in Multiple Myeloma?

Excessive production of light chain antibody fragments Signup and view all the answers

What is the typical age range for the incidence of multiple myeloma?

65 to 70 years Signup and view all the answers

Match the clinical features with the respective lymphomas:

Hodgkin Lymphoma = Painless lymphadenopathy Burkitt Lymphoma = Aggressive and fast-growing Multiple Myeloma = Bone pain and lytic lesions Myelodysplastic Syndrome = Ineffective hematopoiesis Signup and view all the answers

Which characteristic is associated with Hodgkin Lymphoma?

Presents with a single lymph node Signup and view all the answers

Hodgkin lymphoma is characterized by the presence of __________ cells.

Reed-Sternberg Signup and view all the answers

What is the highest frequency of transformation from MDS to AML observed?

t-MDS Signup and view all the answers

Which functional categories do the affected proteins in MDS fall into? (Select all that apply)

Epigenetic factors Signup and view all the answers

Most mutations in MDS are gain-of-function mutations.

False Signup and view all the answers

At what mean age does MDS commonly present?

70 years Signup and view all the answers

Chronic Myeloid Leukemia (CML) only affects children.

False Signup and view all the answers

What genetic alteration characterizes CML?

Translocation of chromosomes 9 and 22 Signup and view all the answers

What is the common clinical feature experienced in CML due to increased cell turnover?

Fatigability Signup and view all the answers

In CML, the accelerated phase is characterized by increasing __________ and thrombocytopenia.

anemia Signup and view all the answers

Match the following terms with their definitions:

Absolute polycythemia = Results from an intrinsic abnormality of hematopoietic precursors Relative polycythemia = Results from dehydration and decreased plasma volume Polycythemia Vera = Characterized by increased marrow production of red cells, granulocytes, and platelets Spent phase of PCV = Characterized by extensive marrow fibrosis Signup and view all the answers

What is the most common mutation found in Langerhans cell histiocytosis?

Valine to glutamate substitution at residue 600 in BRAF Signup and view all the answers

Splenomegaly can lead to hypersplenism characterized by cytopenias.

True Signup and view all the answers

What is anemia defined as?

A reduction of total circulating red cell mass below normal limits. Signup and view all the answers

Which factors characterize hereditary spherocytosis?

All of the above Signup and view all the answers

What is rhinophyma?

Permanent thickening of the nasal skin by confluent erythematous papules and prominent follicles. Signup and view all the answers

What are the main causes of splenomegaly?

Congestion of the cords of Billroth and increased numbers of phagocytes. Signup and view all the answers

What antimicrobial peptide is associated with high cutaneous levels in rhinophyma?

Cathelicidin Signup and view all the answers

What triggers aplastic crises in patients with splenomegaly?

Acute parvovirus infection. Signup and view all the answers

Rosacea is characterized by a specific perifollicular infiltrate of eosinophils.

False Signup and view all the answers

What may occur in the pustular phase of rosacea?

Neutrophils may colonize the follicles, leading to follicle rupture and granulomatous dermal response. Signup and view all the answers

Hemolytic crises are more clinically significant than aplastic crises.

False Signup and view all the answers

Which enzyme deficiency is associated with red cell enzyme defects?

Glucose-6-Phosphate Dehydrogenase (G6PD) Signup and view all the answers

What is panniculitis?

An inflammatory reaction in the subcutaneous adipose tissue. Signup and view all the answers

What is the most common form of panniculitis?

Erythema nodosum Signup and view all the answers

What is the inheritance pattern of G6PD deficiency?

Recessive X-linked trait. Signup and view all the answers

What common condition occurs with erythema nodosum?

Infections, drug administration, or certain diseases. Signup and view all the answers

What are the common variants of G6PD?

G6PD Mediterranean Signup and view all the answers

What is the primary cause behind molluscum contagiosum?

A poxvirus. Signup and view all the answers

Hemoglobin S (HbS) is associated with ____ cell disease.

sickle Signup and view all the answers

Impetigo is commonly caused by ___.

S.aureus Signup and view all the answers

What mutation causes sickle cell disease?

A missense mutation in the β-globin gene. Signup and view all the answers

What term refers to athlete's foot?

Tinea pedis Signup and view all the answers

What is one possible protective effect of sickle cell trait?

Protection against Plasmodium falciparum malaria Signup and view all the answers

Which condition is characterized by erythematous plaques with peripheral scaling?

Tinea corporis Signup and view all the answers

Individuals with sickle cell trait typically experience severe symptoms of sickle cell disease.

False Signup and view all the answers

What are the clinical manifestations of varicella-zoster virus (VZV) infection?

Both A and B. Signup and view all the answers

What is a common clinical feature of sickle cell disease?

Vaso-occlusive crises Signup and view all the answers

What is the mechanism behind the hemolysis in G6PD deficiency?

Reduced ability to protect against oxidative injuries. Signup and view all the answers

What is Lyme disease primarily caused by?

A tick bite that carries Borrelia burgdorferi. Signup and view all the answers

What is the primary pathogen responsible for scabies?

Sarcoptes scabiei Signup and view all the answers

What does a decrease in pH promote in relation to sickle hemoglobin?

Increased sickling of HbS Signup and view all the answers

α-thalassemia is caused by inherited ____ that affect α-globin chain synthesis.

deletions Signup and view all the answers

What is vitiligo?

A condition where pigment disappears from patches of skin. Signup and view all the answers

Which type of leukemia is most common in children?

Acute lymphoblastic leukemia Signup and view all the answers

What is the most severe form of α-thalassemia?

Hydrops fetalis. Signup and view all the answers

Match the following types of acute lymphoblastic leukemia to their characteristics:

B-cell acute lymphoblastic leukemia = Primarily affects children; associated with RUNX1 and ETV6 translocations. T-cell acute lymphoblastic leukemia = Primarily affects adolescent males; associated with thymic masses. Signup and view all the answers

What skeletal change is associated with marked expansion of the bone marrow in response to erythroid hyperplasia?

Prominent cheekbones Signup and view all the answers

Which of the following describes a vaso-occlusive crisis?

Painful episodes due to hypoxic injury and infarction Signup and view all the answers

What complication arises in up to 45% of males with sickle cell disease after puberty?

Priapism Signup and view all the answers

Which of the following factors may trigger a vaso-occlusive crisis?

Dehydration Signup and view all the answers

What condition is characterized by fever, cough, chest pain, and pulmonary infiltrates in patients with sickle cell disease?

Acute chest syndrome Signup and view all the answers

Which microorganism is commonly associated with septicemia and meningitis in sickle cell disease, especially in children?

Pneumococcus pneumoniae Signup and view all the answers

What is a common manifestation of painful bone crises in children with sickle cell disease?

Dactylitis or hand-foot syndrome Signup and view all the answers

What characterizes a papule compared to a nodule?

Papules are 5 mm or less across. Signup and view all the answers

What role does pulmonary inflammation play in vaso-occlusive crisis in sickle cell disease?

Decreases blood flow leading to sickling Signup and view all the answers

What is the primary process involved in the formation of a scar when tissue cannot regenerate?

Connective tissue deposition Signup and view all the answers

Which skin lesion is formed as a result of dermal edema and is often itchy?

Wheal Signup and view all the answers

Which type of tissue is characterized by continuously dividing cells that replenish lost cells?

Labile tissue Signup and view all the answers

What does acanthosis indicate in the context of microscopic skin lesions?

Diffuse epidermal hyperplasia. Signup and view all the answers

Which lesion is characterized by a fluid-filled raised structure greater than 5 mm across?

Bulla Signup and view all the answers

What is the main requirement for the restoration of normal tissue structure during the regeneration process?

Structural integrity of residual tissue Signup and view all the answers

Which factor plays a critical role in the process of cell proliferation during tissue regeneration?

Integrity of extracellular matrix Signup and view all the answers

What is the effect of hyperkeratosis on the skin?

Thickening of the stratum corneum. Signup and view all the answers

What causes lichenification in the skin?

Repeated rubbing leading to thickened skin. Signup and view all the answers

How is spongiosis defined in the context of tissue pathology?

Edema of the epidermis Signup and view all the answers

In the context of secondary skin lesions, what does excoriation involve?

Traumatic lesion causing raw skin. Signup and view all the answers

What initiates the regenerative process in the liver after injury?

Cytokines and growth factors Signup and view all the answers

Dyskeratosis is best described as which of the following?

Premature keratinization of epidermal cells. Signup and view all the answers

What is the consequence of vacuolization in tissue pathology?

Creation of vacuoles within or adjacent to cells Signup and view all the answers

What term is used to describe the condition of the skin that shows complete loss of the epidermis?

Ulceration Signup and view all the answers

What is the predominant age group affected by acute lymphoblastic leukemia (ALL)?

Children younger than 15 years Signup and view all the answers

Which of the following is considered a significant risk factor for the development of acute lymphoblastic leukemia?

Total body irradiation exposure Signup and view all the answers

What type of cells are primarily involved in acute lymphoblastic leukemia?

Immature B and T cells Signup and view all the answers

What underlying genetic alteration is often observed in T-cell acute lymphoblastic leukemia (T-ALL)?

Mutations in the NOTCH1 gene Signup and view all the answers

What clinical feature is commonly associated with T-cell acute lymphoblastic leukemia?

Thymic masses Signup and view all the answers

Which statement about the pathogenesis of vitiligo is true?

Autoimmune mechanisms may be involved. Signup and view all the answers

What is a notable characteristic of B-cell acute lymphoblastic leukemia?

Chromosomal translocations are common. Signup and view all the answers

Which is a common complication arising due to acute lymphoblastic leukemia in children?

Pancytopenia Signup and view all the answers

What is a potential complication of shingles if the geniculate nucleus is involved?

Facial paralysis Signup and view all the answers

Which stage of Lyme Disease is characterized by meningitis and peripheral neuropathy?

Stage II Signup and view all the answers

What is the primary mechanism through which Lyme disease causes pathology in the body?

Secondary immune response Signup and view all the answers

What is the characteristic appearance of skin lesions in scabies?

Linear burrows and dry scales Signup and view all the answers

Which of the following is a severe symptom of Rocky Mountain Spotted Fever appearing shortly after the bite?

Headache and fever Signup and view all the answers

Which condition is classified as a medical emergency when associated with shingles?

Eye involvement Signup and view all the answers

What is a common method of transmission for scabies?

Close physical contact Signup and view all the answers

Which of the following symptoms is NOT typically associated with early Lyme Disease?

Oligoarticular arthritis Signup and view all the answers

What condition is characterized by multiple small seborrheic keratoses on the face in people of color?

Dermatosis papulosa nigra Signup and view all the answers

What is a common feature of actinic keratosis?

Development of cutaneous horns due to keratin production Signup and view all the answers

Which type of carcinoma is typically the second most common tumor arising on sun-exposed skin in older individuals?

Squamous cell carcinoma Signup and view all the answers

What is a significant risk associated with actinic keratosis in terms of progression?

Progressively worsening dysplastic changes leading to squamous cell carcinoma Signup and view all the answers

What histological feature helps differentiate seborrheic keratoses from melanoma?

Impact keratin in small, round ostia Signup and view all the answers

What is the primary risk factor for developing t-MDS?

Exposure to ionizing radiation Signup and view all the answers

Which of the following mutations is most frequently observed in MDS compared to AML?

Loss-of-function mutations in TP53 Signup and view all the answers

Which clinical feature is most directly associated with the progression of MDS?

Thrombocytopenia Signup and view all the answers

What type of clinical outcome correlates with complex karyotypes in MDS?

Particularly poor clinical outcomes Signup and view all the answers

Which mutational category is implicated in deranged differentiation in MDS?

Transcription factors Signup and view all the answers

In which age group is chronic myeloid leukemia (CML) predominantly diagnosed?

Primarily a disease of older adults Signup and view all the answers

Which of the following chromosomal abnormalities is most frequently associated with MDS?

Monosomy 5 Signup and view all the answers

What aspect of MDS is most directly related to pyrimidine metabolism in its pathogenesis?

RNA splicing Signup and view all the answers

What symptom is most commonly associated with shingles when affecting the trigeminal nerves?

Facial paralysis Signup and view all the answers

Which stage of Lyme disease is characterized by meningitis and cranial nerve palsies?

Stage II Signup and view all the answers

What type of rash is typically associated with Rocky Mountain Spotted Fever?

Maculopapular Signup and view all the answers

What is the primary cause of symptoms in Lyme disease?

Immune response to the spirochete Signup and view all the answers

Which clinical manifestation is NOT typically observed in the early stages of scabies?

Joint swelling Signup and view all the answers

What is the correct time frame for scabies larvae to hatch after eggs are laid?

3-4 days Signup and view all the answers

What is a key diagnostic feature of shingles that differentiates it from other conditions?

Dermatomal distribution Signup and view all the answers

What type of rash would NOT typically be found in the progression of Lyme disease?

Exudative rash Signup and view all the answers

Which protein is MOST commonly affected by mutations in hereditary spherocytosis leading to a deficiency?

Ankyrin Signup and view all the answers

What is the expected average lifespan of red blood cells in hereditary spherocytosis?

10 to 20 days Signup and view all the answers

Which clinical feature is characteristic of hereditary spherocytosis?

Spherocytes in blood smear Signup and view all the answers

What triggers an aplastic crisis in patients with hereditary spherocytosis?

Acute parvovirus infection Signup and view all the answers

Which condition occurs in 40% to 50% of affected adults with hereditary spherocytosis?

Choletlitiasis (pigment stones) Signup and view all the answers

What mechanism mainly leads to the formation of spherocytes in hereditary spherocytosis?

Loss of membrane versus cytoplasm Signup and view all the answers

What type of genetic inheritance pattern is most commonly associated with hereditary spherocytosis?

Autosomal dominant Signup and view all the answers

Which of the following is NOT a feature commonly seen in hemolytic anemias, including hereditary spherocytosis?

Hypochromic microcytic anemia Signup and view all the answers

What is the primary cause of anemia in α-thalassemia?

Inadequate hemoglobin synthesis and excess unpaired globin chains Signup and view all the answers

Which genotype is more likely to result in symptomatic α-thalassemia in Asian populations?

Deletion of two α-globin genes from a single chromosome Signup and view all the answers

What characterizes the silent carrier state of α-thalassemia?

Deletion of a single α-globin gene with minimal symptoms Signup and view all the answers

In which vascular beds is sickling most likely to occur due to slow transit times?

Normal spleen and bone marrow Signup and view all the answers

Which factor contributes to slowed blood flow in inflamed tissues?

Adhesion of leukocytes to endothelial cells Signup and view all the answers

What determines the severity of α-thalassemia?

The number of affected α-globin genes Signup and view all the answers

Which population is at greater risk for classic symptomatic α-thalassemia conditions such as HbH disease?

Individuals from Asia Signup and view all the answers

What is the significance of HbA2 levels in α-thalassemia trait?

They are typically normal or low Signup and view all the answers

Study Notes

Skin Lesions

Primary lesions are original appearances of skin conditions; secondary lesions are modified by time or external factors (e.g., scratching).
Assessment includes family/personal history, geographic origin, season, occupation, and any prior diseases or treatments.

Macroscopic and Microscopic Lesions

Excoriation: Traumatic linear defect in the epidermis, often self-induced.
Lichenification: Thickened, rough skin due to repeated rubbing.
Macule/Patch: Flat color-distinguished lesions; macules ≤5 mm, patches >5 mm.
Onycholysis: Separation of nail plate from nail bed.
Papule/Nodule: Elevated lesions ≤5 mm (papule) or >5 mm (nodule).
Plaque: Elevated flat-topped lesion >5 mm, may form from coalescent papules.
Pustule: Pus-filled raised lesion.
Scale: Dry, plate-like excrescence from imperfect cornification.
Vesicle/Bulla: Fluid-filled lesions ≤5 mm (vesicle) or >5 mm (bulla).
Wheal: Itchy, transient lesion with edema.

Tissue Repair Processes

Healing restores tissue architecture post-injury via regeneration or scar formation.
Regeneration involves replacement of damaged tissue returning to normal function.
Scarring occurs when tissues can't regenerate due to severe damage.

Cell and Tissue Regeneration

Involves cell proliferation influenced by growth factors and the extracellular matrix (ECM).
Tissues are categorized as labile (continuously dividing), stable (quiescent), and permanent (non-dividing).
Example: Liver regeneration is triggered by cytokines and growth factors after tissue loss.

Connective Tissue Deposition

Involves fibroblasts and collagen synthesis when regeneration is incomplete.
Granulation tissue forms first, leading to scar formation.
Primary closure: edges of a wound are closely approximated; secondary closure: wound fills from the base and surroundings.

Defects in Healing

Venous leg ulcers: common in elderly due to chronic venous hypertension, slow to heal from poor oxygen delivery.
Arterial ulcers: caused by atherosclerosis, painful and necrotic due to ischemia.
Diabetic ulcers: develop in lower extremities, resulted from vascular disease and neuropathy.
Pressure sores: skin necrosis from prolonged compression on tissues.
Hypertrophic scars: excessive collagen, raised lesions that may regress.
Keloids: grow beyond original wound boundaries, do not regress, more common in certain populations.

Injury by Physical Agents

Mechanical trauma: injury patterns vary (abrasions, lacerations).
Thermal injury: categorized by burn depth:
- 1st Degree (Superficial): affects epidermis, healing in days.
- 2nd Degree (Partial Thickness): involves dermis, moist with blisters, heals in weeks.
- 3rd Degree (Full Thickness): reaches subcutaneous tissue, painless, often requires surgical intervention.

Burn Shock and Complications

Massive fluid shifts leading to hypovolemia and risk of shock.
Respiratory dysfunction: resulting from inhalation injuries; ARDS can develop.
Renal dysfunction: arises from low blood volume or nephrotoxic agents.
Metabolic changes: hypermetabolism and protein breakdown due to stress.

Immune Response

Burns can suppress immune function, increasing infection risk.
Cytokine release and inflammatory response can lead to multisystem organ failure.

Melanocytic Nevus

Common benign neoplasms caused by mutations in RAS signaling.
Appearance: uniformly pigmented, well-defined borders, usually <6 mm.

Dysplastic Nevi and Melanoma

Dysplastic nevi may precede melanoma; they're larger and demonstrate cytologic atypia.
Melanoma is aggressive and highly linked to UV exposure. Important indicators: asymmetry, irregular borders, variegated color, and diameter changes (≥6 mm is concerning).
Familial predispositions may involve mutations affecting cell cycle control and telomerase expression.

Treatment for Burns

Varies by burn degree, often includes rehydration and potentially surgical intervention for deep burns.### Skin Tumors
Melanoma transitions from a superficial spreading-radial growth phase to a vertical growth phase, marked by nodule formation and potential metastatic subclones.

Benign Epithelial Tumors

Seborrheic Keratosis*
Common in middle-aged and older individuals, spontaneously arising on the trunk and extremities.
In people of color, small facial lesions termed dermatosis papulosa nigra affect up to 35% of African-American adults.
Often linked to activating mutations in FGFR3, promoting tumor growth.
Appears as flattened or raised warts with a "pasted-on" look, exhibiting various colors.
Microscopically, reveals keratin-impacted pore-like ostia, aiding in differentiation from melanoma.

Premalignant and Malignant Epidermal Tumors

Actinic Keratosis*
Develops in sun-damaged skin, typically <1 cm, and shows hyperkeratosis.
Can progress to cutaneous squamous cell carcinoma with dysplastic changes.
Commonly tan-brown, red, or skin-colored with a rough texture; some may form "cutaneous horns."
Typically found on sun-exposed areas like the face and hands; may stabilize but can necessitate eradication.
Squamous Cell Carcinoma*
Second most prevalent skin tumor in older adults, with a higher occurrence in men.
Presents as nodular lesions, with less than 5% metastasizing to regional nodes.
Main risk factor is UV-induced DNA damage, with incidence correlating to lifetime sun exposure.
P53 gene dysfunction occurs early in tumor development.
Basal Cell Carcinoma*
Most common invasive cancer in humans, characterized by slow growth and rare metastasis.
Associated with mutations activating the Hedgehog signaling pathway.
Often presents as pearly papules with telangiectasias on sun-exposed skin.
Neglect may lead to advanced invasive lesions involving bone or facial sinuses.

Acute Inflammatory Dermatoses

Urticaria (Hives)*
Result from localized mast cell degranulation leading to dermal hyperpermeability, creating pruritic wheals.
Affects individuals of all ages, often between 20-40 years.
Forms can be IgE-dependent, involving allergic reactions, or IgE-independent, from direct mast cell degranulation.
Localized factors can trigger forms, including aspirin-induced and hereditary angioneurotic edema.
Acute Eczematous Dermatitis*
Results from T-cell mediated inflammatory reactions (type IV hypersensitivity), categorized into five types.
Allergic Contact Dermatitis: triggered by external antigens, with symptoms appearing within 48 hours and displaying crusted lesions.
Atopic Dermatitis: genetic factors and epidermal barrier defects are key; common in children with dry, itchy lesions.
Other types include drug-related, photoeczematous, and primary irritant dermatitis.
Erythema Multiforme*
Hypersensitivity reaction associated with infections, drugs, and malignancies.
Characterized by diverse lesions, including targetoid appearances and systemic complications.
Severe forms like Stevens-Johnson syndrome involve lesions on mucous membranes.

Chronic Inflammatory Dermatoses

Psoriasis*
Autoimmune disorder affected by genetic and environmental factors.
Characterized by well-defined, pink-salmon plaques with silver-white scaling, especially on elbows and knees.
Types include plaque psoriasis, guttate psoriasis, inverse psoriasis, and erythrodermic psoriasis, each with unique presentations.
Nail psoriasis may cause discoloration, pitting, and onycholysis.

Disorders of Epidermal Appendages

Acne Vulgaris*
Affects adolescents and young adults, with more severe cases in males.
Induced by factors like drugs and hormonal changes, leading to follicular plugging.
Features open (blackheads) and closed (whiteheads) comedones; bacterial colonization by Propionibacterium acnes contributes to inflammation.
Rosacea*
Common in middle-aged individuals, classified into four stages from flushing to rhinophyma.
Characterized by lymphocyte infiltration and neutrophilic responses during the pustular phase.

Panniculitis

Erythema Nodosum*
Presents with tender erythematous plaques, often linked to infections, medication, and malignancies.
Pathogenesis involves delayed hypersensitivity reactions with lesions that may resolve without scarring.
Molluscum Contagiosum*
Self-limiting viral skin infection caused by a poxvirus, often in children, presenting as firm umbilicated papules.
Impetigo*
Highly contagious bacterial skin infection, commonly in children, differentiated into contagiosa and bullosa forms based on pustule size, primarily caused by S. aureus.

Superficial Fungal Infections

Commonly caused by Trichophyton Rubrum, they can manifest as tinea in various body locations, such as the scalp (tinea capitis), body (tinea corporis), or groin (tinea cruris).

Varicella-Zoster Virus (VZV) Infections

Causes chickenpox in initial infection and shingles upon reactivation, with more severe consequences in adults and immunocompromised individuals.### Varicella-Zoster Virus (VZV)
VZV causes latent infections in sensory ganglia and evades immune responses.
It spreads through respiratory aerosols and leads to widespread vesicular skin lesions, unlike herpes simplex virus (HSV).
Latent infections occur in dorsal root ganglia neurons and satellite cells; reactivation may result in shingles years later.
Shingles frequently occurs in skin areas supplied by the trigeminal ganglia, causing significant pain.

Physical Manifestations of VZV

Chickenpox rash appears about 2 weeks post-respiratory infection, starting as macules and progressing to vesicles resembling dewdrops.
Vesicles rupture, crust over, and heal without scarring, but secondary bacterial infections can cause scarring.
Shingles presents as vesicular lesions accompanied by severe pain due to radiculoneuritis; involvement of trigeminal nerves can lead to facial paralysis (Ramsay Hunt syndrome).
Dermatomal lesions are unilateral; ocular involvement is a medical emergency.

Lyme Disease

Caused by tick bites transmitting Borrelia burgdorferi, leading to immune response-related pathology.
Affects skin, nervous system, heart, and musculoskeletal system.
Stage I presents with erythematous papules and flu-like symptoms (Bull's-eye rash).
Stage II includes meningitis and cranial nerve palsies; stage III manifests as oligoarticular arthritis.

Scabies

Caused by Sarcoptes scabiei, which lays eggs in the stratum corneum; transmission occurs via close contact.
Symptoms include small erythematous papules with crusts and severe itching, often accompanied by linear burrows.

Tick-Borne Illness: Rocky Mountain Spotted Fever

Result of a tick bite from Rickettsia rickettsii, often reported in many states.
Initial bite shows a papule or macule; after 4 to 8 days, headache, fever, nausea, and muscle aches appear, along with a rash on the wrists and ankles.

Acute Lymphoblastic Leukemia/Lymphoma (ALL)

Composed of immature B or T cells (lymphoblasts); most common cancer in children.
Roughly 2500 new cases annually in the U.S.; predominates in those under 15 years old and is more common among Caucasians.
Pathogenesis involves chromosomal aberrations that disrupt normal B/T cell development, leading to aggressive manifestation.
Symptoms include bone pain, anemia, leukopenia, and thrombocytopenia.

Burkitt Lymphoma

Three categories: endemic (African), sporadic (nonendemic), and HIV-associated.
Characterized by MYC gene translocation on chromosome 8, resulting in rapid tumor growth.
Comprises about 30% of childhood non-Hodgkin lymphomas in the U.S., presenting predominantly in children and young adults.
Endemic type often involves the mandible and abdominal viscera; sporadic type commonly presents as a mass in the ileocecum.

Multiple Myeloma

Arises from bone marrow plasma cells; incidence is higher in men and African descent individuals.
Characterized by lytic bone lesions, hypercalcemia, renal failure, and moderate aggressiveness.
Diagnosed with presence of clonal plasma cells and CRAB criteria: hypercalcemia, renal dysfunction, anemia, and bone lesions.
Symptoms include severe bone pain, pathological fractures, and renal issues due to Bence Jones proteinuria.

Skin and Hematology Overview

Primary lesions: Initial skin changes with original appearance.
Secondary lesions: Changes due to progression over time or external influences, such as scratching.

Skin Lesion Classification

Macroscopic Lesions

Excoriation: Raw linear defect from epidermis break, often self-inflicted.
Lichenification: Thickened, rough skin due to repeated rubbing.
Macule and Patch: Flat lesions; macules ≤5 mm; patches >5 mm.
Onycholysis: Nail plate separation from nail bed.
Papule and Nodule: Elevated lesions; papules ≤5 mm; nodules >5 mm.
Plaque: Flat-topped lesion >5 mm.
Pustule: Discrete, pus-filled lesion.
Scale: Dry, plate-like excrescence from imperfect cornification.
Vesicle, Bulla, Blister: Fluid-filled lesions; vesicles ≤5 mm; bullae >5 mm.
Wheal: Itchy elevated lesions formed by dermal edema.

Microscopic Lesions

Acanthosis: Epidermal hyperplasia.
Dyskeratosis: Premature keratinization beneath the stratum granulosum.
Erosion: Partial epidermis loss; skin discontinuity.
Exocytosis: Infiltration of inflammatory cells into the epidermis.
Hydropic swelling: Edema of keratinocytes, often seen in viral infections.
Hypergranulosis: Increased stratum corneum thickness.
Hyperkeratosis: Thickened stratum corneum from keratin abnormalities.
Lentiginous: Melanocyte proliferation in the basal epidermal layer.
Papillomatosis: Dermal papillae hyperplasia causing surface elevation.
Spongiosis: Intercellular edema in the epidermis.
Ulceration: Complete epidermis loss exposing dermis or subcutis.
Vacuolization: Vacuole formation within or around cells.

Tissue Repair Mechanisms

Repair: Restoration of tissue post-injury via regeneration or scarring.
Regeneration: Tissue replacement returning to normal cellular state.
Scar Formation: Occurs when regeneration isn't feasible or structural framework is damaged.

Cell and Tissue Regeneration

Involves proliferation driven by growth factors, dependent on extracellular matrix (ECM) integrity.
Tissues categorized as labile (continuously dividing), stable (limited turnover), and permanent (no regeneration).
Liver Regeneration: Initiated by cytokines and growth factors after liver mass loss; involves surviving hepatocytes or progenitor cell repopulation.

Skin Conditions

Shingles: Causes vesicular lesions, associated with itching and pain; presents unilaterally following dermatomes.
Lyme Disease: Tick-borne infection by Borrelia burgdorferi; affects skin, nervous, heart, and musculoskeletal systems with distinct stages of symptoms, including a "Bull's eye rash."
Scabies: Caused by Sarcoptes scabiei; characterized by severe itching and small papules with burrows.

Tick-Borne Illness

Rocky Mountain Spotted Fever

Pathogenesis: Result of Rickettsia rickettsii carried by ticks; enters bloodstream.
Clinical Features: Initial bite appears as papule/maculopapule, followed by fever, headache, and rash.

Vitiligo (Leukoderma)

Pathogenesis: Sudden pigment loss from skin patches; causes remain unclear, with theories including autoimmune, viral, genetic, and neurochemical factors.

Acute Lymphoblastic Leukemia/Lymphoma (ALL)

Cell Lineage: Composed of immature B (pre-B) or T (pre-T) lymphoblasts.
Epidemiology: Most common cancer in children, ~2,500 new cases annually in the U.S.
Marrow Changes: Hyperplastic bone marrow leads to prominent craniofacial changes.
Pathophysiology: Bone pain crises, acute chest syndrome, and susceptibility to severe infections due to opsonization defects.

Dermatological Conditions

Dermatosis papulosa nigra is common in people of color, with up to 35% of African-American adults affected.
Activating mutations in fibroblast growth factor receptor-3 (FGFR3) are often found in sporadic seborrheic keratoses, promoting tumor growth.
Seborrheic keratoses can appear as flattened or raised growths, ranging in color from pink to black, often having a "pasted-on" look.
Examination with a hand lens may reveal keratin-impacted ostia, aiding in distinguishing these lesions from melanoma.

Premalignant and Malignant Tumors

Actinic Keratosis

Typically arises from sun-damaged skin, showcasing hyperkeratosis.
Can progress to cutaneous squamous cell carcinoma with dysplastic changes.
Lesions are usually under 1 cm, presenting tan-brown, red, or skin-colored with a rough texture.
Some lesions may develop "cutaneous horns" due to excessive keratin production.
Commonly found on sun-exposed areas such as the face, arms, and hands; treatment may include curettage, freezing, or topical chemotherapeutics.

Squamous Cell Carcinoma

The second most frequent skin tumor in older adults, following basal cell carcinoma.
More prevalent in men; lesions are nodular and may ulcerate.
Smaller, resectable invasive squamous cell carcinomas are often discovered early.

Viral Conditions

Shingles

Characterized by vesicular lesions, frequently accompanied by severe itching and pain from radiculoneuritis.
Severe pain occurs especially with involvement of the trigeminal nerves; facial paralysis may result if the geniculate nucleus is impacted (Ramsay Hunt syndrome).
Lesions follow dermatomes, presenting unilaterally; ocular involvement is a medical emergency.

Lyme Disease

Caused by a tick bite transmitting Borrelia burgdorferi.
Symptoms result primarily from the immune response to the infection and associated inflammation.
Stage I features include itchy erythematous papules and flu-like symptoms (Bull's eye rash); Stage II can involve meningitis and cranial nerve palsies; Stage III is associated with oligoarticular arthritis.

Scabies

Caused by Sarcoptes scabiei; begins with egg-laying in the stratum corneum.
Transmission occurs through close contact with an infested individual.
Characterized by small erythematous papules, dry scaling or crust, and severe itching.

Tick-Borne Illness

Rocky Mountain Spotted Fever

Transmitted by ticks carrying Rickettsia rickettsii; reported cases exist across most states.
Initial bite appears as a papule or macule, with subsequent headache, fever, nausea, and a macular rash typically on wrists and ankles within 4 to 8 days.

Bone Marrow and Blood Disorders

Myelodysplastic Syndromes (MDS)

Developed if transformation occurs post-genotoxic exposures, with symptoms manifesting typically 2-8 years later.
Associated mutations overlap with acute myeloid leukemia (AML), particularly affecting epigenetic factors, RNA splicing machinery, and transcription factors.
Primarily affects older adults with average onset at 70; symptoms include weakness, infections, and bleeding due to pancytopenia.

Chronic Myeloid Leukemia (CML)

Predominantly affects adults but occurs in children and adolescents; characterized by abnormal proliferation of myeloid lineage cells.

Hereditary Spherocytosis (HS)

Results from mutations affecting membrane skeletal components, generally inherited in an autosomal dominant manner in about 75% of cases.
Affected red cells have a lifespan of 10-20 days compared to the normal 120 days; spherocytes lose deformability and are prone to splenic destruction.
Characteristic features include splenomegaly, reticulocytosis, and potential aplastic crises following viral infections like parvovirus.

Alpha-Thalassemia

Caused by inherited deletions resulting in decreased α-globin synthesis.
Severity is linked to the number of affected α-globin genes, with more severe forms occurring with multiple gene deletions.
Silent carrier state involves one α-globin gene deletion, while α-thalassemia trait involves two deletions. Symptomatic complications arise primarily in Asian populations.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the classification of skin lesions, including primary and secondary types, and their macroscopic and microscopic characteristics. Understanding the various lesions such as papules, pustules, and their assessments is crucial for dermatological practice.