DERMVEE.docx

Acne Vulgaris **Overview** - **Common Presentation:** Especially prevalent during puberty. - **Description:** Can present with pustules and vesicles. **Demographics** - **Prevalence:** 80% of people seek medical care for acne at some point. - **Age Group:** Most common in teens and...

Acne Vulgaris **Overview** - **Common Presentation:** Especially prevalent during puberty. - **Description:** Can present with pustules and vesicles. **Demographics** - **Prevalence:** 80% of people seek medical care for acne at some point. - **Age Group:** Most common in teens and early adulthood. **Etiology** - **Multifactorial:** Androgens play a significant role. - **Andrenarche:** Increases sebum production, common in teenagers. - **Comedones:** Lesions due to lipid and keratin accumulation in follicular units. - **Blackhead:** Open comedone exposed to air, causing oxidation and black discoloration. - **Whitehead:** Closed comedone with intact skin covering. **Pathogenesis** - **Comedone Formation:** - **Process:** Accumulation of lipid and keratin in the follicular unit. - **Location:** Commonly on the face. - **Bacterial Involvement:** Cutibacterium acnes - **Growth:** Overgrows in sebum and lipid-rich environments. - **Oil Reference:** Sebum and lipid accumulation within comedones. - **Inflammatory Response:** - - - **Morphology** - **Open Comedone:** Leads to blackhead due to oxidation. - **Closed Comedone:** Appears as a whitehead. - **Nodules:** Larger lesions involving dermal inflammation. - **Nodulocystic Lesions:** Severe form, often with systemic symptoms, more common in teenage males. **Management** - **Topical Antiseptics:** Benzoyl peroxide to reduce bacterial count and prevent comedones. - **Oral Antibiotics:** Tetracyclines (e.g., doxycycline, minocycline). - **Side Effects:** Photosensitivity, drug-induced lupus, pseudotumor cerebri (the patient presents with headaches and increased intracranial pressure. Fundoscopic exam shows papilledema, while imaging shows nothing because it\'s a pseudotumor.) - **Vitamin A Derivatives:** - **Topical Retinoids:** Tretinoin to prevent comedones and reduce inflammation. - **Oral Retinoid:** Isotretinoin for severe nodulocystic scarring acne. - **Side Effects:** Teratogenicity, pseudotumor cerebri, hyperlipidemia. **Differential Diagnosis** - **Acne Rosacea:** - **Demographics:** Adults, especially Northern European descent. - **Triggers:** Stress, spicy food, etc. - **Symptoms:** Erythema, flushing, telangiectasia, absence of comedones. - **Rhinophyma:** Bulbous nose, sometimes associated with alcoholism. - **Perioral/Periocular Dermatitis:** - **Location:** Around mouth or eyes. - **Appearance:** Inflammatory papules without comedones. - **Cause:** Often follows topical steroid use. - **Folliculitis:** - **Location:** Predominantly trunk and extremities. - **Symptoms:** Infection of hair follicle. - **Progression:** Can lead to furuncles, carbuncles, and abscesses if untreated. - **Allergic Contact Dermatitis Overview** - **Definition:** Allergic contact dermatitis is a delayed hypersensitivity reaction (type 4) triggered by direct contact with an allergen. - **Timing:** Symptoms typically appear 1-2 days after exposure to the allergen. - **Common Allergens:** - **Metals:** Nickel (e.g., from jewelry). - **Chemicals:** Chromates (from leather), neomycin (topical antibiotics), para-phenylenediamine (hair dye). - **Plants:** Poison ivy, poison oak, causing linear distribution of lesions upon contact. - **Morphology:** - Well-demarcated erythematous plaques that may weep and are intensely pruritic. - Linear pattern along areas of contact, especially with plant allergens like poison ivy. **Management** - **Identify and Avoid Allergen:** Withdrawal of the offending allergen is crucial. - **Topical Steroids:** For localized reactions to reduce inflammation and itching. - **Systemic Steroids:** Consider for widespread disease or severe reactions. **Differential Diagnosis** - **Atopic Dermatitis:** Associated with genetic predisposition and immune dysregulation, often presenting as eczematous plaques with a predilection for flexural areas. **Alopecia Areata (AA)** - **Definition**: Alopecia means loss of hair. Alopecia areata specifically involves non-scarring hair loss, often associated with autoimmune processes. - **Types**: - **Alopecia totalis**: Total loss of scalp hair. - **Alopecia universalis**: Loss of all body hair. - **Pathophysiology**: Autoimmune attack on hair follicles by lymphocytes. - **Management**: - Topical steroids - Intralesional steroids - Oral steroids - Light treatment - **Differential Diagnoses**: - **Tinea capitis**: Fungal infection of the scalp characterized by erythema, scaling, and sometimes bogginess. Diagnosed via KOH examination. - **Cutaneous lupus erythematosus**: Inflammatory condition with pigmentary changes, can cause scarring alopecia unlike alopecia areata. - **Trichotillomania**: - Non-scarring hair loss due to compulsive hair pulling. - Most common in young girls with psychiatric disturbances. - No autoimmune component; distinguished by the act of hair plucking. **Angioedema Overview:** - **Definition:** Angioedema is characterized by localized, non-pitting edema involving deeper layers of the skin and mucosal membranes. - **Types:** - **Hereditary Angioedema (HAE):** - Caused by a deficiency or dysfunction of C1 inhibitor (C1-INH). - Presents with recurrent episodes of angioedema without urticaria (hives). - Low C4 levels due to unopposed complement activation and consumption. - Management involves replacing C1-INH, often with fresh frozen plasma (FFP). - **Acquired Angioedema:** - More common than HAE. - Can be associated with medications like ACE inhibitors, causing increased bradykinin levels due to decreased degradation. - Presents with angioedema and may include symptoms like a dry cough. - Unlike urticaria (hives), acquired angioedema does not involve wheal formation or superficial vasodilation. - **Mechanism:** - HAE involves genetic defects affecting complement regulation. - Acquired forms can result from medications or underlying conditions affecting bradykinin metabolism. - **Clinical Features:** - Deep, non-pitting swelling affecting areas like the lips, eyes, hands, feet, and genitals. - Mucosal involvement can lead to potentially life-threatening airway compromise. - **Management:** - **Hereditary Angioedema:** - Replace deficient C1-INH with FFP or specific C1-INH concentrates. - **Acquired Angioedema (ACE Inhibitor-Induced):** - Discontinue ACE inhibitors. - Manage symptoms with supportive care, antihistamines, IV steroids, and possibly epinephrine if there is airway compromise. - **Differentiation from Urticaria:** - Angioedema involves deeper tissues and mucosal membranes, lacking the superficial wheal formation seen in urticaria. - Urticaria is associated with Type 1 hypersensitivity reactions and manifests with transient wheals and itching due to histamine release. **Atopic Dermatitis** **Atopic Dermatitis Overview:** - **Definition:** Atopic dermatitis is a common inflammatory skin condition characterized by eczematous plaques. - **Association:** Often associated with atopic diseases like asthma and allergic rhinitis, forming the atopic triad. - **Immunological Basis:** Involves type 1 hypersensitivity reactions mediated by IgE and helper T cells (Th2). - **Multifactorial Causes:** Influenced by genetic predisposition (e.g., mutations in filaggrin gene), environmental allergen exposure (e.g., pollen), and immune dysregulation. - **Hygiene Hypothesis:** Suggests that reduced early childhood exposure to allergens may increase susceptibility to atopic diseases. - **Epithelial Barrier Disruption:** Structural abnormalities in the epidermis contribute to increased permeability to irritants and allergens. - **Demographics:** Increasing incidence, particularly prevalent in childhood, often improves with age. **Clinical Features:** - **Morphology:** Eczematous plaques, often weeping and extremely pruritic. - **Age-Dependent Location:** - Infants: Face and extensor surfaces (cheeks). - Older children and adults: Flexural areas (e.g., antecubital and popliteal fossae). **Associations:** - **Ichthyosis:** Fish-like scaling of the skin. - **Keratosis Pilaris:** Rough, goosebump-like skin on the arms. - **Dennie-Morgan Lines:** Fold lines beneath the lower eyelids due to chronic rubbing. **Management:** - **Education:** Emphasize avoidance of triggers and allergens. - **Skin Care:** Gentle bathing, application of emollients to maintain skin hydration. - **Treatment:** - **Topical Steroids:** Anti-inflammatory agents to reduce inflammation and itching. - **Antihistamines:** Manage pruritus associated with allergic reactions. **Differential Diagnosis:** - **Contact Dermatitis:** Caused by direct contact with allergens like nickel in jewelry, leading to type 4 hypersensitivity reactions. - **Seborrheic Dermatitis:** Characterized by erythematous plaques with greasy scales, commonly affecting facial areas including the nasolabial folds in adults and scalp (cradle cap) in infants. **Basal Cell Carcinoma (BCC, Basal Cell Cancer)** **Overview** - Basal cell carcinoma (BCC) is the most common cancer worldwide in humans. - Chronic intermittent UV exposure is a possible risk factor for BCC. - BCC originates in the basal layer, the bottommost layer of the epidermis. - Morphology of BCC includes pearly papule or a nodule with central ulceration and umbilication on sun-exposed skin. - BCC typically appears above the upper lip, by the nose, or in any area exposed to UV rays. - BCC has a very low risk of metastasis, around 0.05%, but can be locally aggressive and disfiguring. **Clinical Presentation** - BCC may present as a pearly papule or nodule with central ulceration and umbilication. - Commonly found above the upper lip, by the nose, or on sun-exposed skin. - While metastasis is rare, BCC can grow locally and quickly, leading to disfigurement. - Demographics: Most common in older adults and occurs on sun-exposed areas. - Locally aggressive but slow-growing, with less than 0.05% chance of metastasis. - Histologically, BCC involves proliferation of basophilic cells from the basal epidermis infiltrating the dermis. **Management** - Superficial BCC forms can be managed with curettage, electrodessication, excision, or Imiquimod Cream. For other forms of BCC, excision and micrographically controlled surgery are considered, especially for aggressive cases **Benign Nevus and Dysplastic Nevus** **Nevus Overview** - **Definition**: A nevus is a cluster of melanocytes. - **Appearance**: Depending on the depth in the skin: - Epidermal nevi give a pigmented or brownish appearance. - Dermal nevi do not significantly alter skin pigmentation as melanocytes are deeper in the dermis. **Types of Nevus** 1. **Benign Nevus:** - **Common Nevus**: Symmetric, uniform, without atypia. - Benign and lacks increased concern for malignancy. 2. **Dysplastic Nevus:** - **Characteristics**: Irregular shape, variegated pigmentation, atypical cytology. - **Risk**: Considered preneoplastic, requiring proper follow-up to monitor for progression to melanoma. - **Dysplastic Nevus Syndrome (DNS)**: Inherited disorder increasing risk for melanoma. 3. **Histological Types**: - **Junctional Nevus**: Melanocytes at dermoepidermal junction. - Macular lesion, hyperpigmented. - **Compound Nevus**: Melanocytes extend into dermis. - Papular lesion. - **Intradermal Nevus**: Melanocytes confined to dermis. - Minimally pigmented compared to junctional and compound nevi. **Clinical Features of Dysplastic Nevus (Atypical Nevus)** - **A through E Criteria**: - **Asymmetry**: Uneven shape. - **Border irregularity**: Jagged or notched borders. - **Color variegation**: Multiple shades within the same nevus. - **Diameter**: Greater than 6 millimeters. - **Evolution**: Changes in size, shape, or color over time. **Diagnostic Considerations** - **Differential Diagnoses**: Includes melanoma, seborrheic keratosis, and cherry hemangioma. - **Clinical Presentation**: - **Seborrheic Keratosis**: Stuck-on appearance, benign, pigmented. - **Cherry Hemangioma**: Dome-shaped red papule, benign, increases with age. **Clinical Evaluation** - **Benign Nevus**: Symmetrical, uniform, \6 mm diameter, elevated (papular). **Erythema Migrans (Lyme Disease)** **Definition and Characteristics** - **Erythema migrans** or erythema chronicum migrans is a target lesion associated with Lyme disease. - It appears as a central area of erythema surrounded by pallor, then by a ring of erythema resembling a dartboard or target. - Caused by the spirochete bacteria *Borrelia burgdorferi* transmitted by the Ixodes tick, particularly *Ixodes scapularis* in the Northeastern United States. **Clinical Features** - May present with fever and arthralgia. - Initial manifestation of Lyme disease following tick bite. **Management** - **Doxycycline** is the preferred treatment for erythema migrans associated with Lyme disease. **Fifth Disease (Erythema Infectiosum)** **Definition and Characteristics** - **Fifth disease** or erythema infectiosum is caused by parvovirus B19, a single-stranded DNA virus. - It manifests with a characteristic \"slapped cheek\" appearance followed by a lacy, reticular rash on the trunk and extremities. **Clinical Features** - Symptoms may include fever and coryza (head cold). - The rash presents in a reticular (network-like) pattern on the skin. **Complications and Considerations** - Pregnant women exposed to parvovirus B19 are at risk of **hydrops fetalis** in the fetus. - Can cause transient aplastic anemia due to bone marrow suppression, particularly in individuals with underlying hemolytic disorders like sickle cell disease. **Management** - Management focuses on supportive care as the virus is usually no longer infectious once the rash appears. - Monitoring and management of complications, especially in pregnant women and those with underlying hematologic conditions. - **Definition**: - Infection of the hair follicle, often bacterial (typically Staphylococcus aureus). - Can progress to furuncles, carbuncles, and abscesses. - **Demographics and Pathophysiology**: - Can occur at any age. - Involves both terminal and vellus hairs. - Staphylococcus aureus is the most common causative agent. - Gram-negative bacteria may cause cases in the groin. - **Clinical Presentation**: - Severity varies based on degree of inflammation. - Image shows infected hair follicle unit. - **Management**: - Oral antibiotics like dicloxacillin or cephalexin. - Consider culture for non-responsive cases. - Incision and drainage for large, fluctuant lesions. - Packing and marsupialization rarely needed. - **Differential Diagnoses**: - **Acne vulgaris**: Typically in pubertal age group, comedones are characteristic. - **Prurigo nodularis**: Neurodermatitic excoriation, not follicular-based. - **Miliaria (prickly heat)**: Occlusion of eccrine sweat ducts, extravasation of sweat into dermis, common in body folds. **Dermatology - Inflammatory Disorders** **General Terminology** **Macule** - Definition: Flat, non-palpable lesion. - Example: Café au lait spot. - Characteristics: Mocha-colored, less than 1 cm. **Patch** - Definition: Flat, non-palpable lesion larger than a macule. - Characteristics: Greater than 1 cm. **Papule** - Definition: Elevated, palpable lesion. - Characteristics: Less than 1 cm. **Plaque** - Definition: Flat-topped elevation. - Example: Psoriasis. - Characteristics: Greater than 1 cm, often salmon-colored. **Nodule** - Definition: Round, palpable elevation. - Example: Rheumatoid nodule. - Characteristics: Less than 2 cm. **Tumor** - Definition: Swelling, elevation greater than 2 cm. **Fluid-Filled Lesions** **Vesicle** - Definition: Clear fluid-filled blister. - Examples: Herpes, Chickenpox, Porphyria cutanea tarda. - Characteristics: Less than 1 cm, can be painful. **Pustule** - Definition: Pus-filled blister. - Characteristics: Less than 1 cm. **Bulla** - Definition: Large fluid-filled blister. - Examples: Pemphigoid vulgaris, Bullous pemphigoid. - Characteristics: Greater than 1 cm. **Erosions and Ulcers** **Erosion** - Definition: Loss of part of the epidermis. **Ulcer** - Definition: Full thickness loss of the epidermis. \_\_\_\_\_\_ What type of skin lesion is greater than 1 cm in size and not palpable? - Top of Form - Patch Bottom of Form What type of skin lesions are most typical of psoriasis? - - Plaques What do you call a fluid-filled lesion with a diameter greater than 1 cm? - Bulla **Herpes Simplex Virus (HSV)** - **Virus Types**: HSV-1 and HSV-2 can both cause genital herpes in men and women, with HSV-2 historically more associated but HSV-1 increasingly causing genital infections in recent years. - **Clinical Presentation**: - Lesions appear 2-12 days after sexual contact, starting as painful vesicles that progress to red papules, pustules, erosions, and ulcers. - Viral particles are present in these lesions. - **Pregnancy Concerns**: - Pregnant women with herpes infections can transmit the virus to newborns during delivery if shedding the virus. - Involvement of the cervix or vagina can lead to severe leukorrhea (genital discharge). - **Differential Diagnosis**: - Leukorrhea can occur in both herpes and candida infections, though the organisms and presentations differ significantly. - **Healing and Latency**: - Genital herpes lesions typically heal in 2-3 weeks, but the virus remains latent in nerve ganglia, similar to other herpesviruses. - **Complications**: - Neonatal herpes infection, part of the TORCH complex, can lead to severe conditions like herpes encephalitis affecting the frontotemporal region of the brain in newborns. - **Etiology**: - Reactivation of latent Varicella-zoster virus (VZV). - Typically occurs in individuals who have had chickenpox or rarely in those vaccinated with the now unavailable live Varicella vaccine. - **Clinical Features**: - Presents as a painful dermatomal rash. - More common in the elderly and can be triggered by severe stress. - **Morphology**: - Characterized by vesicles filled with fluid, followed by crust formation. - Typically follows a unilateral distribution along a dermatome. - **Epidemiology**: - Most common in elderly individuals and those with immunosuppression. - Diagnosis often clinical in immunocompetent patients due to characteristic presentation. - **Diagnostic Methods**: - PCR testing is preferred for diagnosis due to high sensitivity. - Tzanck smear can be performed if PCR or viral culture is unavailable, showing multinucleated keratinocytes. - **Management**: - **Antiviral medications**: Acyclovir, valacyclovir, or famciclovir should be started within 72 hours of rash onset. - **Pain management**: Short-term use of opioids and possibly steroids for acute pain; however, steroids do not reduce post-herpetic neuralgia risk. **Hives (Urticaria)** **Urticaria (hives)** is characterized by its rapid onset of wheals and erythema due to histamine **release from mast cells in response to IgE-mediated hypersensitivity reactions. Management** focuses on identifying triggers and providing symptomatic relief through antihistamines, tailored to the patient\'s sedation needs and response. - **Definition:** Urticaria, commonly known as hives, is an IgE-mediated Type 1 hypersensitivity reaction triggered by exposure to specific antigens. - **Mechanism:** - Antigen exposure leads to IgE isotype switching and binding to mast cell receptors. - Mast cells release histamine upon activation. - Histamine causes vasodilation, leading to edema and erythema. - **Triggers:** - Food, medications, exercise, temperature changes, vibration, and stress can provoke hives. - **Chronic Urticaria:** Defined as 2 -- 3 episodes per week for at least 6 weeks. - **Morphology:** - Rapid onset of localized edema (wheals) with erythematous borders. - Wheals evolve and resolve within 24 hours. - Blanching occurs when pressure is applied due to dispersal of edema fluid. - **Diagnosis:** - Typically clinical based on history and physical examination. - Biopsy is rarely necessary. - **Management:** - **Identify Trigger:** Determine and avoid the causative allergen or trigger. - **Antihistamines:** - **Sedating:** Diphenhydramine. - **Moderately Sedating:** Cetirizine. - **Non-Sedating:** Loratadine (consider based on patient\'s needs). - **Other Treatments:** Consider corticosteroids for severe cases or when antihistamines are ineffective. **Impetigo** - **Definition:** Superficial skin infection caused by either streptococcus or staphylococcus. - **Comparison with Cellulitis and Erysipelas:** - Cellulitis is deeper, erysipelas is rapid and fiery red (St. Anthony's fire), both caused by streptococcus. - **Demographics:** Common in children, often on the central face. - **Clinical Features:** Honey-crusted lesions, especially around the mouth (perioral area). - **Complication:** If caused by streptococcus, can lead to post-streptococcal glomerulonephritis about 4 weeks later. - **Diagnosis:** Clinical appearance, culture (no serologic test for strep). - **Management:** Oral antibiotics, topical mupirocin ointment. **Staphylococcal Scalded Skin Syndrome (SSSS)** - **Cause:** Exfoliation due to toxin produced by Staphylococcus aureus infection. - **Affected Population:** Infants and individuals with renal failure are most commonly affected. - **Management:** Intravenous antibiotics such as vancomycin or nafcillin, along with supportive care. **Malignant Melanoma** **Risk Factors** - **Sun exposure**, especially at an early age. - **Blistering sunburns** in childhood. - **Intermittent sun exposure**. - **Family history**: melanoma in a first or second-degree relative. - **Genetic predisposition**: Familial melanoma, p16(Ink), B-Raf (vemurafenib). - **Fair complexion**: Light or red hair, light eyes. **Clinical Features** - **New or changing mole**. - **ABCDE Criteria**: Asymmetry, Border irregularity, Color variegation, Diameter (\>6 mm), Evolution. **Growth Patterns** - **Radial Growth**: - Lateral proliferation along the dermoepidermal junction. - Less likely to invade and metastasize. - **Vertical Growth**: - Downward invasion into the dermis. - Increased risk of metastasis. - Single most important prognostic factor is depth of invasion. **Epidemiology** - Increasing incidence: 1 in 65 in the U.S. - Prognosis is best determined by depth of invasion. **Management** - **Complete excision** of the primary lesion and any metastatic lesions. - **Sentinel lymph node biopsy**: For lesions \>0.8 mm thickness or ulcerated lesions. - **Adjuvant systemic immunotherapy**: Checkpoint inhibitors or targeted therapy. - **Preventive Measures**: - Avoid UV rays. - Recommended protective clothing and shady areas. - Avoid peak sun hours (10 a.m. - 4 p.m.). - Sunblock is recommended, though evidence of risk reduction is unclear. **Differential Diagnosis** - **Atypical Nevus**: - Violates ABCDE criteria. - Early melanomas may not be reliably discriminated from atypical nevus. - Biopsy required for confirmation. - **Seborrheic Keratosis**: - Pigmented, \"stuck-on\" appearance. - Occurs in elderly, may be autosomal dominant. - Leser-Trélat sign indicates association with GI cancer. - **Actinic Lentigo (Liver Spots)**: - Macular lesion from chronic sun exposure. - Common in elderly. - Small, sharply circumscribed, and homogeneously pigmented. **Melasma (Chloasma)** **Definition and Characteristics** - **Melasma** is a common dermatologic disorder characterized by hyperpigmentation, typically appearing as light to dark brown patches on the face. - It is more prevalent in pregnant women (often postpartum), individuals using oral contraceptive pills, or undergoing hormone replacement therapy. - The exact cause is not fully understood but involves overproduction of melanin, likely influenced by hormonal changes (especially estrogen) and sun exposure. **Clinical Features** - Appears as homogenous, light to dark brown macules on sun-exposed areas of the face, such as the cheeks, forehead, nose, and upper lip. - The lesions are macular (flat), without elevation or scaling. **Management** - **Photoprotection:** Advised to avoid UV exposure and use protective clothing, hats, and sunscreen (broad-spectrum SPF 30 or higher). - **Discontinuation of Provoking Agents:** If melasma is associated with oral contraceptive pills or hormone replacement therapy, discontinuation may be recommended. - **Topical Treatments:** Include **hydroquinone** and other bleaching agents to lighten the pigmented areas for cosmetic purposes. - **Combination Therapy:** Sometimes hydroquinone is combined with other agents like tretinoin and corticosteroids for enhanced efficacy. **Demographics** - More common in individuals with darker skin tones, especially Hispanics and Asians. **Special Considerations** - Management may require long-term sun protection and topical treatments to prevent recurrence and maintain results. **Onychomycosis** **Definition and Characteristics** - **Onychomycosis** refers to a fungal infection of the nail plate or nail bed. - \"Onycho-\" relates to nails. - Caused by dermatophytes or occasionally saprophytes. - Commonly affects elderly individuals (20% prevalence). **Clinical Features** - Causes thickened, dystrophic, and discolored nails. - May lead to nail crumbling and onycholysis (separation of the nail from the nail bed). **Diagnosis** - Diagnosis is confirmed through methods like KOH preparation or nail biopsy. **Management** - Treatment involves confirming the diagnosis before initiating therapy. - Topical treatments are typically used for fingernails. - Oral antifungals like terbinafine or itraconazole are necessary for prolonged courses, especially in diabetics or those with mobility issues. **Scabies** **Definition and Characteristics** - **Scabies** is an infestation caused by the mite *Sarcoptes scabiei*. - Mites burrow into the superficial skin, laying eggs and feces, triggering an allergic reaction. **Clinical Features** - Presents with a pruritic rash. - Characterized by small linear burrows, often found on wrists and between fingers. - Typically spares the face, neck, and scalp in adults. **Diagnosis** - Diagnosis involves a scabies prep, where burrows are scraped and examined microscopically. - Identification of mites, eggs, or feces confirms the diagnosis. **Management** - Topical treatment with permethrin is effective. - Oral ivermectin is an alternative, especially in severe cases. - Treatment should include all family members, and thorough laundering of linens is essential to prevent reinfestation. **Primary Varicella (Chickenpox)** - **Clinical Features**: - Vesicles with \"dew drops on rose petals\" appearance. - Less common in vaccinated children, can be severe in adults. - **Complications**: - VZV pneumonia. **Candidiasis** - **Etiology**: - Candida is a normal skin commensal but can become pathogenic when overgrown. - **Demographics**: - Diabetic, obese individuals, and those involved in wet work (e.g., bartenders) are predisposed. - **Clinical Manifestations**: - **Intertriginous Candidiasis**: Erythema and pustules in body folds (e.g., groin area). - **Oral Thrush**: Creamy white plaques in the oral mucosa that can be scraped off. - **Perleche**: Fissuring and erythema in the oral commissures. - **Other Types**: Esophageal candidiasis, vulvovaginal candidiasis, and invasive candidiasis. - **Identification**: - Approximately 160 known Candida species, with about 20 responsible for human infections. - **Candida albicans** is the most common pathogen. - **Risk Factors**: - Antibiotic use, immune impairment, hormonal changes, uncontrolled diabetes, poor hygiene, corticosteroid use, poorly fitted dentures, and excessive alcohol consumption. - **Candida auris**: Notable for antifungal resistance and significant threat in healthcare settings. - **Immune Response**: - A strong immune system can prevent or mitigate infections, while a weakened immune system can exacerbate them. - **Diagnosis**: - KOH examination to identify yeast overgrowth, pseudohyphae indicative of pathologic overgrowth. - **Management**: - **Topical Azoles**: Used for skin infections. - **Nystatin**: Powder or cream for skin, mouthwash for oral thrush. - **Clotrimazole Troches**: For oral thrush. **Psoriasis** - **Demographics**: - Affects 1% to 3% of Americans. - Often familial; one-third of patients report family history. - Genetic and environmental triggers implicated. - **Morphology**: - Salmon-colored erythematous plaques with thick silver scales. - Commonly found on elbows, knees, scalp, and gluteal clefts. - Pruritus is a common complaint. - **Nail Changes**: - Pitting, oil spots, and nail loss. - Important diagnostic features. - **Triggers and Associations**: - Exacerbated by lithium and beta blockers. - Streptococcal infections can trigger guttate psoriasis. - **Complications**: - Psoriatic arthritis involves vertebral and joint deformities (HLA-B27 association). - **Pathology**: - Epidermal thickening (acanthosis). - Absent or thin granular layer. - Parakeratosis with neutrophil microabscesses. - **Management**: - Topical treatments (vitamin D derivatives, steroids). - Oral retinoids (vitamin A derivatives). - Systemic therapies: methotrexate, cyclosporine, biologics (TNF inhibitors). - Light therapy (phototherapy) if available. - **Differential Diagnoses**: - **Eczema or dermatitis**: Weeping vesicles, exudative appearance. - **Secondary syphilis**: Smaller plaques with plasma cells and spirochetes on biopsy. - **Tinea corporis**: Scaling border with central clearing, often mistaken for ringworm. **Rosacea** - Rosacea has various presentations, including rhinophyma. - Rhinophyma shows no comedones, erythema, and telangiectasia. - Triggers include spices, alcohol, stress, sunlight/wind, hot temperatures, and caffeine. - Rosacea is more common in adults, especially Northern Europeans, and affects women more than men. - Men often have rhinophyma with erythematous telangiectasia changes. - Poorly understood etiology involves blood vessels and possibly Demodex mites. - Morphology includes papules and pustules, usually on the central face, with mandatory telangiectasia. - Management includes metronidazole, azelaic acid, tetracycline derivatives, and cosmetic procedures like rhinophymectomy and laser treatment. - Differential diagnoses include acne vulgaris (with comedones), perioral/periocular dermatitis (monomorphic inflammatory papules), and systemic lupus erythematosus (sparing nasolabial fold). - Seborrheic dermatitis as a differential shows intense pruritus, greasy yellow scale, and involves nasolabial folds, glabella, and hairline. **Seborrheic Dermatitis** - **Initial Observation:** - Do not confuse with malar rash of SLE, rhinophyma of rosacea, or acne. - Patient may appear older. - **Key Differentials:** - Rosacea, Acne Vulgaris, Malar Rash of SLE. - **Clarification:** - Seborrheic dermatitis, **not** seborrheic keratosis (associated with Leser-Trélat sign). - **Description:** - Greasy, yellow scale. - Presence of erythema. - May involve nasolabial area, eyebrows, scalp, and chest. - **Differential Details:** - SLE: Does not involve the nasolabial fold due to photosensitivity. - Infant Presentation: Dandruff-like, termed \"cradle cap.\" - **Management:** - Antifungal creams or washes. - Mild topical steroids. - **Etiology:** - Aberrant reaction involving pityrosporum yeast. - Management includes antifungal or topical steroid. - **Presentation Range:** - From simple dandruff in infants (cradle cap) to more extensive flaking on the scalp. - **Demographics:** - 80% of dermatologic conditions are acne vulgaris; seborrheic dermatitis is in the remaining 10-15%. - Increases with age. - **Differential Diagnoses:** - **Psoriasis:** - Salmon-colored plaque, more scale, less waxy. - Involves skin outside seborrheic areas (nasolabial fold, scalp, chest). - **Superficial Dermatomycosis (Tinea):** - Tinea capitis (scalp), tinea jock itch (inguinal), tinea unguium (nail). - Often bogginess or significant scalp inflammation. - **Acute Systemic Lupus Erythematosus (SLE):** - Involves maxillary skin, spares nasolabial fold. - Opposite of seborrheic dermatitis. - **Clinical Pearls:** - SLE spares the nasolabial fold. - Rosacea triggers: stress, spicy food, alcohol, sun, wind, hot temperatures. - Rosacea in males often affects the nose (rhinophyma) with telangiectasia. **Seborrheic Keratosis** - **Definition**: A common benign epidermal tumor consisting of immature keratinocytes. - **Epidemiology**: Very common in the elderly; over 65% of individuals older than 80 may have multiple seborrheic keratoses. - **Inheritance**: Thought to be inherited in an autosomal dominant fashion, often associated with cherry angiomas. - **Malignant Potential**: Possesses no malignant potential under normal circumstances. - **Leser-Trélat Sign**: Rare paraneoplastic syndrome where multiple seborrheic keratoses abruptly appear, associated with various malignancies. - **Morphology**: Lesions are sharply circumscribed, resembling a **stuck-on** piece of chocolate, appearing white-yellow to brown. - **Management**: Typically requires no treatment; may be removed if inflamed, traumatized, or symptomatic. - **Differentiation**: Not to be confused with seborrheic dermatitis or actinic keratosis. **Pathology** - **Acanthotic**: Thickened epidermis with overlying hyperkeratosis and a sharply demarcated base. **Actinic Keratosis** - **Definition**: Premalignant condition caused by UV exposure. - **Clinical Features**: Lesions feel gritty (like sandpaper) and can progress to squamous cell carcinoma if untreated. - **Skin Cells Involved**: Arise from squamous cells of the skin. - **Premalignant Nature**: Actinic keratosis is considered the first true premalignant condition due to its potential to progress to squamous cell carcinoma. - **Management**: Requires intervention to prevent progression to skin cancer; treatments include various methods of removal. **Tinea Infections (Ringworm): Tinea Corporis and Tinea Capitis** **Definition and Characteristics** - **Tinea** refers to fungal infections of the skin caused by dermatophytes. - These infections are superficial dermatomycoses. - Dermatophytes are fungi that utilize keratin as their energy source. **Key Organisms** - **Trichophyton** and **Microsporum** are primary dermatophytes causing tinea infections. **Types of Tinea** - **Tinea Capitis**: Affects the scalp, characterized by hair loss (alopecia) and may present with black dots (broken hair shafts). - **Tinea Corporis**: Affects the body, commonly known as ringworm, despite having no relation to worms. - **Tinea Pedis**: Affects the feet (athlete\'s foot). - **Tinea Cruris**: Affects the groin area (jock itch). - **Tinea Unguium**: Affects the nails (onychomycosis). - **Tinea Versicolor**: Causes hypopigmented and hyperpigmented patches on the skin, caused by *Malassezia furfur*. **Clinical Features** - Lesions are often well-demarcated annular plaques with active scaling. - Lesions can be intensely pruritic, especially in areas prone to sweating. **Diagnosis** - Diagnosis often involves a KOH preparation to visualize fungal hyphae. - Commonly identified organism in tinea capitis is *Trichophyton tonsurans*. **Management** - Treatment includes topical antifungals like ketoconazole. - Oral antifungals may be necessary for refractory infections. **Alopecia and Tinea Capitis** - Tinea capitis can lead to alopecia where the hair shafts break off, leaving black dots. **Summary** - Tinea infections are superficial fungal infections caused by dermatophytes affecting various parts of the body. - Diagnosis involves clinical evaluation and microscopic identification of fungal hyphae. Management includes topical and oral antifungal therapies depending on the severity and location of the infection **Verruca (Plantar Wart)** - **Differential Diagnoses**: - **Squamous cell carcinoma**: Sun-exposed areas, larger lesions, elderly. - **Corn or clavus**: Pressure areas, lacks central thrombosed capillaries. - **Seborrheic dermatitis**: Greasy, yellowish appearance. - **Condyloma lata**: Secondary syphilis, paramucosal lesions, positive RPR test. - **Types of Warts and Associated HPV Strains**: - **Verruca vulgaris**: HPV 2, common in children (think \"terrible two's\"). - **Verruca plana**: HPV 3 and 10. - **Verruca plantar**: HPV 1. - **Condyloma acuminata**: HPV 6 and 11 (low-risk strains). - **Genital warts**: HPV 16, 18, 31, 33 (high-risk strains). - **Pathophysiology and Morphology**: - Acanthotic epidermis, papillomatosis, hyperkeratosis, hypergranulosis. - Dilated vessels in dermis due to thickening. - Different HPV types dictate wart appearance and location. - **Clinical Features and Management**: - Most resolve with time in children; treatment aims to hasten resolution. - Destructive techniques: Liquid nitrogen, cantharidin, podophyllin. - **Imiquimod cream**: Approved for genital warts. - Challenges in immunocompromised patients. - **Prevention and Vaccination**: - Gardasil vaccine targets HPV strains, including those causing genital warts and high-risk strains. **Vitiligo** **Definition and Characteristics** - **Vitiligo** is characterized by an autoimmune-mediated loss of melanocytes, leading to hypopigmented (depigmented) patches on the skin. - The condition presents as macular depigmentation, contrasting with conditions like melasma, which involve hyperpigmentation. **Clinical Features** - Commonly affects areas such as eyelids, nipples, hands, elbows, and knees. - Skin appears hypopigmented, often with well-defined borders between affected and unaffected skin. - Distribution can vary widely and is noticeable particularly in patients with darker skin tones. **Demographics** - Occurs in individuals of all ages and races, but more notably in those with darker skin tones. - Onset can occur at any age, with peak incidence often in early adulthood. **Management** - **Topical Steroids:** Potent topical corticosteroids are often used to suppress autoimmune activity and encourage repigmentation. - **Light Therapy (Phototherapy):** UVB light treatment can help stimulate melanocyte activity and repigmentation of affected areas. - **Camouflage Makeup:** Cover-up cosmetics can be used to conceal depigmented areas for cosmetic purposes and to improve patient confidence. **Long-term Care** - Management may require ongoing treatment and sun protection to manage symptoms and prevent progression. - Psychological support is essential due to the visible nature of the condition and its potential impact on self-esteem.