dermsg1.docx

**[Week 13 Dermatology :]** **[Sequela of varicella]** Varicella-zoster virus (VZV) is a linear, double-stranded DNA virus in the *Herpesviridae* family. Varicella-zoster infections are highly contagious and transmitted through aerosolized respiratory droplets or contact with infected skin lesions...

**[Week 13 Dermatology :]** **[Sequela of varicella]** Varicella-zoster virus (VZV) is a linear, double-stranded DNA virus in the *Herpesviridae* family. Varicella-zoster infections are highly contagious and transmitted through aerosolized respiratory droplets or contact with infected skin lesions. Chickenpox is the primary infection and occurs most commonly in children. The typical clinical presentation includes prodromal symptoms and a generalized, intensely pruritic vesicular rash. Shingles (also known as herpes zoster) is more common in adults and occurs due to the reactivation of VZV. The diagnosis is primarily clinical. Management is supportive, although antiviral therapy can be used in certain patient populations. Complications can include secondary bacterial infections, encephalitis, or pneumonia. Varicella-zoster vaccine is recommended as a preventive measure in early childhood. **[What is onychomycosis?]** Causes thickened, dystrophic, and discolored nails. 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. **[Furuncle, carbuncle, and abscess]** A furuncle, also known as a boil, is a painful, pus-filled bump that forms on the skin when bacteria infects a hair follicle. The bacterium that causes furuncles is Staphylococcus aureus (S. aureus), which is commonly found on the skin and in the nose. While S. aureus is usually harmless, it can cause infections of varying severity if it enters deeper tissue A carbuncle is a skin infection that\'s a cluster of boils that form a connected area of infection. It\'s caused by bacteria entering the skin through a broken area, such as a cut, scratch, or puncture wound, and infecting multiple hair follicles. The immune system responds by sending white blood cells to the area, which causes inflammation and the formation of a pus-filled carbuncle An abscess is a painful, swollen lump filled with pus that can develop anywhere in the body. It\'s usually caused by a bacterial infection, such as E. coli, enterococcus, staphylococcus, or streptococcus. When the body\'s immune system fights an infection, white blood cells travel to the infected area and build up in the damaged tissue, causing inflammation and the formation of a pocket. This pocket fills with pus, which is made up of living and dead white blood cells, germs, fluid, and dead tissue **[Symptoms of atopic dermatitis]** Very common, exposure to allergens, associated with Asthma, allergic type of rhinitis Type 1 hypersensitivity reaction with helper type 2 t cells Family hx can predispose, elevated cord IgE, early childhood exposure to microbes can prevent epithelial barrier disruption This is most common in childhood, highly pruritic eczematous plaques Locations change with age -- face and extensor in infants, flexural areas in older children and adults Associated with Ichthyosis -fishy, scaling skin Keratosis pilaris Denny Morgan lines Wheeping vesicle appearance Manage with education, gentle bathing, generous emoillients, topical steroids and antihistamines for itchiness **[Organisms causing common skin d/o (thrush, impetigo, varicella, etc.)]** **[Risks, presentation, and treatment of common derm ]** **[abnormalities (scabies, impetigo, tinea, atopic dermatitis, rosacea, acne, seborrheic dermatitis, folliculitis)]** Acne Vulgaris -nodules arise from follicle, inflammatory, rupture, nodulocystic lesions can yield systemic symptoms -- often in teen boys Management -- topical antiseptics -- BENZOYL PEROXIDE Oral antibiotics -tetracyclines, doxycycline -- can cause photosensitivity All tetracyclines can cause pseudomotor cerebri Minocycline can cause drug induced lupus! Topical retinoids -- tretinoin Oral retinoids -- Isotretinoin is reserved for severe nodulocystic scarring acne, be very careful due to teratogenicity, pseudomotor cerebri, hyperlipidemia [Rosacea] -- northern European adults, central face with flushing ,background erythema, telangiestias, comedones are NOT a feature, may have a bulbous nose Stress can trigger, can also be caused by alcohol, found in adulthood, women more impacted but when seen in men they will have rhinophymaa, sunlight can trigger, spicy foods, hot temp of foods, caffeine There will be involvement of blood vessels -- vasoactivity, "flushers and blushers" To have rosacea diagnosed MUST have telangiectasias (minute dilated blood vessels) Another cause is demodex -- oil mites Manage with: Metronizadole, azelaic acid, tetracycline derivatives with anti inflammation properties, cosmetic procedure -rhinophmectomy and laser treatment for telangiectasias [Perioral/Periocular dermatitis:] Can follow topical steroid use, monomorphic, occurs in specific areas, inflammatory papules without comedones [Folliculitis-] hair follicle infection, trunk and extremities, can lead to furuncles, carbuncles, abscesses **[SEBORRHEIC DERMATITIS:]** Greasy, yellow scale Nasolabial area, eyebrows, scalp, chest, called "cradle cap" in infants Treat with creams or washed, mild topical steroids It is an aberrant reaction to pityrosporum yeast, can range from simple dandruff to severe disease **[ATOPIC DERMATITIS:]** Very common, exposure to allergens, associated with Asthma, allergic type of rhinitis Type 1 hypersensitivity reaction with helper type 2 t cells Family hx can predispose, elevated cord IgE, early childhood exposure to microbes can prevent epithelial barrier disruption This is most common in childhood, highly pruritic eczematous plaques Locations change with age -- face and extensor in infants, flexural areas in older children and adults Associated with Ichthyosis -fishy, scaling skin Keratosis pilaris Denny Morgan lines Wheeping vesicle appearance Manage with education, gentle bathing, generous emoillients, topical steroids and antihistamines for itchiness [**ALLERGIC CONTACT DERMATITIS**:] Type 4 immune reaction that appears 24-48 hours after contact, a good example is poison ivy, others include nickel, hair dye, leather, cement Common sources in the workplace and hobbies Well demarcated erythematous and weeping plaques, very itchy Linear distribution when due to contact with plants Use topical and systemic steroids to treat **[HIVES (Uticaria)]** IgE mediated type one histamine is released, caused by food,medication, exercise, temperature,vibration, stress 2-3 episodes a eek for 6 weeks is chronic uticaria Rapid development of edema, erythematous wheel formation, flare lesion Lesions evolve and dissipate rapidly within 24 hours, they are blanchable Biopsy is rarely performed Superficial dermal edema, perivascular and interstitial inflammatory cell infiltration of lymphocytes Minimal change in the epidermis Lymphatic channel dilation Manage with antihistamines: Sedating -- diphenhydramine, hydroxyzine Moderate -- Cetirizine Non Sedating -- Loratadine **Scabies** -- mite infestation, in immunocompromised can see millions Female mites burrow under skin and drop feces and eggs Allergic reaction from the mite matter Burrows are common in finger webs and wrists Adults -face, neck, scalp, usually spared DX by scraping the burrows Treat with topical Premethrin, oral invermetcin **[TINEA INFECTIONS:]** Fungal infection with dermatophyte microsporum -trichophyton Organisms use keratin as energy source Tinia capitus -- scalp Tinia corpitus -- body "ring worm" - no worm Tinia pedis -- foot Tinia crurus- jock itch Tina Versicolor -hypo and hyperpigmented areas, Malassezia furfur organism Well demarcated, intensely itchy Trichophoytn is the most common Management -Ketoconazole, oral if infection is refractory to topical Impetigo is a bacterial skin infection caused by: Staphylococcus aureus: causes 80% of cases, both bullous and non-bullous forms Streptococcus pyogenes (group A beta-hemolytic streptococcus): causes approximately 10% of cases, non-bullous forms only S. aureus and S. pyogenes co-infection: occurs in approximately 10% of cases **IMPETIGO** Primary impetigo: bacterial infection of intact, healthy skin Secondary impetigo (impetiginization): more common, secondary infection of pre-existing skin lesions, such as scabies, insect bites, small cuts, eczema, etc. Transmission: Highly contagious Spread by direct contact with lesions or with nasal carrier Risk factors Children aged 2--5 years Skin trauma (e.g., abrasion, lacerations, animal bite, or sting) Poor hygiene Crowded conditions Warm, humid weather (increased incidence in the summer) Participation in sports with skin-to-skin contact Diabetes mellitus Malnutrition **[Clinical features associated with rosacea]** [Rosacea] -- northern European adults, central face with flushing ,background erythema, telangiestias, comedones are NOT a feature, may have a bulbous nose Stress can trigger, can also be caused by alcohol, found in adulthood, women more impacted but when seen in men they will have rhinophymaa, sunlight can trigger, spicy foods, hot temp of foods, caffeine There will be involvement of blood vessels -- vasoactivity, "flushers and blushers" To have rosacea diagnosed MUST have telangiectasias (minute dilated blood vessels) Another cause is demodex -- oil mites Manage with: Metronizadole, azelaic acid, tetracycline derivatives with anti inflammation properties, cosmetic procedure -rhinophmectomy and laser treatment for telangiectasias **[Know terminology associated with common skin lesions (papule, pustule, comedone, etc.)]** Macule- lesion \1cm not palpable example -Vitaglio Papule -elevation \1cm, flat topped, example -- psoriasis Nodule -- rounded elevation \2cm, swelling Vesicle -clear fluid filled blister \8mm thick or smaller if ulcerated **[Know ABCDE]** ABCDE -increased risk for melanoma\ Asymmetry Birregular boarders Color changes Diameter\>6mm Elevated **[Patho of acne vulgaris]** Pustles, vesicle, happens in the puberty years Multifactorial: Adrenarch increased sebum production Comedones form due to accumulation of lipid and keratin in follicular unit Bacteria An abundance of oil Bacteria convert serum into fatty acids that elicit inflammatory response Open comedones are "blackheads" -- an oxidized keratin plug Closed comedones are "whiteheads", papules without oxidization, potential for follicular rupture and inflammation Acne Vulgaris -nodules arise from follicle, inflammatory, rupture, nodulocystic lesions can yield systemic symptoms -- often in teen boys Management -- topical antiseptics -- BENZOYL PEROXIDE Oral antibiotics -tetracyclines, doxycycline -- can cause photosensitivity All tetracyclines can cause pseudomotor cerebri Minocycline can cause drug induced lupus! Topical retinoids -- tretinoin Oral retinoids -- Isotretinoin is reserved for severe nodulocystic scarring acne, be very careful due to teratogenicity, pseudomotor cerebri, hyperlipidemia **[What is folliculitis?]** Infection of hair follicle, usually bacterial, almost always staph aurus Can be caused by negative gram bacteria as well Degree of inflammation dictates presentation, culture and susceptibility testing Oral antibiotics -Dicloxacillin or Cephalexin 25% recurrence, incision or drainage of large lesions, packing is not required **[Understand urticaria patho and management]** [HIVES (Uticaria)] IgE mediated type one histamine is released, caused by food,medication, exercise, temperature,vibration, stress 2-3 episodes a eek for 6 weeks is chronic uticaria Rapid development of edema, erythematous wheel formation, flare lesion Lesions evolve and dissipate rapidly within 24 hours, they are blanchable Biopsy is rarely performed Superficial dermal edema, perivascular and interstitial inflammatory cell infiltration of lymphocytes Minimal change in the epidermis Lymphatic channel dilation Manage with antihistamines: Sedating -- diphenhydramine, hydroxyzine Moderate -- Cetirizine Non Sedating -- Loratadine **[Define nevus]** - **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. **Common Nevus**: Symmetric, uniform, without atypia. - Benign and lacks increased concern for malignancy. **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. 1. **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)** - **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).