Carlos Shared "15 Dermatology" - 35 Picmonics
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15 Dermatology
Skin Layers
- Skin has 3 layers: epidermis, dermis, subcutaneous fat (hypodermis, subcutis).
- Stratum Corneum (keratin), Stratum Lucidum, Stratum Granulosum, Stratum Spinosum (desmosomes), Stratum Basale (stem cell site)
- Palms and Soles have Lucidum skin
Epithelial cell junctions
Albinism
- albinism
- Normal melanocyte number with decreased melanin production
- Due to decreased tyrosinase activity or defective tyrosine transport.
- Increased risk of skin cancer
- Acquired through locus heterogeneity - Mutations at different loci can produce a similar phenotype.
- Autosomal recessive
- Ocular albinism is X-linked recessive
Melasma (Chloasma)
- Hyperpigmentation associated with pregnancy (“mask of pregnancy”) or OCP use.
Vitiligo
- Pathophysiology
- Autoimmune Destruction of Melanocytes
- Presentation
- Hypopigmentation
- Acral Areas and Around Orifices
- Diagnosis
- Clinical Presentation + Woods Lamp
- Risk Factors
- Other Autoimmune Diseases
- Treatment
- Glucocorticoids
- Tacrolimus
- Phototherapy
2 mins
Acne Vulgaris
- Multifactorial etiology
- Increased sebum/androgen production
- Abnormal keratinocyte desquamation
- Inflammation (papules/pustules, nodules, cysts)
- Propionibacterium acnes colonization of the pilosebaceous unit (comedones)
- Treatment includes retinoids, benzoyl peroxide, and antibiotics
- pathoma
- Comedones (whiteheads and blackheads), pustules (pimples), and nodules; extremely common, especially in adolescents
- Due to chronic inflammation of hair follicles and associated sebaceous glands
- Hormone-associated increase in sebum production (sebaceous glands have androgen receptors) and excess keratin production block follicles, forming comedones.
- Propionibacterium acnes infection produces lipases that break down sebum, releasing proinflammatory fatty acids; results in pustule or nodule formation
- Treatment also includes vitamin A derivatives (e.g., isotretinoin), which reduce keratin production. Isotretinoin is teratogenic, do not give to pregnant mothers.
Atopic Dermatitis / Eczema
- Presentation
- Pruritic Vesicles
- Inflammatory Skin Rash
- Cheeks in Children
- Skin Flexural Areas
- Associated with Asthma and Allergic Rhinitis
- Treatment
- Tacrolimus
- Moisturizers
- Corticosteroids
- Phototherapy
- Avoid Triggers
- Antihistamines
2 mins
Allergic contact dermatitis
- Type IV hypersensitivity reaction that follows exposure to allergen
- Lesions occur at site of contact (eg, nickel, poison ivy, neomycin).
- Pruritic, erythematous, oozing rash with vesicles and edema
- Arises upon exposure to allergens such as
- Poison ivy and nickel jewelry (type IV hypersensitivity)
- Irritant chemicals (e.g., detergents)
- Drugs (e.g., penicillin)
- Treatment involves removal of the offending agent and topical glucocorticoids, if needed.
Melanocytic nevus/Junctional Nevus
- Common mole.
- Benign, but melanoma can arise in congenital or atypical moles.
- Intradermal nevi are papular
- Junctional nevi are flat macules
Pseudofolliculitis barbae
- Foreign body inflammatory facial skin disorder characterized by firm, hyperpigmented papules and pustules that are painful and pruritic
- Located on cheeks, jawline, and neck.
- Commonly occurs as a result of shaving (“razor bumps”)
- Primarily affects African-American males
Psoriasis
- Presentation
- Epidermal Hyperproliferation Keratinocytes
- Defined Red Salmon Plaques
- Silvery Scales
- Extensor Surfaces
- Bleeding when Removed
- Auspitz Sign
- Pruritus
- Nail Changes
- Histological Finding
- Munro Microabscesses
- Nucleated Cells in Stratum Corneum
- Treatment
- Retinoids
- Topical Corticosteroids
- Tar
- Immunosuppressants
2 mins
Rosacea
- Inflammatory facial skin disorder characterized by erythematous papules and pustules, but no comedones.
- May be associated with facial flushing in response to external stimuli (eg, alcohol, heat).
- Phymatous rosacea (chronic rosacea) can cause rhinophyma (bulbous deformation of nose).
Seborrheic keratosis
- Flat, greasy, pigmented squamous epithelial proliferation with keratin-filled cysts (horn cysts)
- Coin-like, waxy, 'stuck-on' appearance
- Lesions occur on head, trunk, and extremities.
- Characterized by keratin pseudocysts on histology
- Common benign neoplasm of older persons.
- Leser-Trélat sign —sudden appearance of multiple seborrheic keratoses, indicating an underlying malignancy (eg, GI or lymphoid (less common)).
Verrucae
- Warts; caused by HPV (Usually 6 and 11)
- Soft, tan-colored, cauliflower-like papules
- Epidermal hyperplasia, hyperkeratosis, koilocytosis.
- Condyloma acuminatum on genitals
Urticaria (Hives)
- Also known as Hives
- Pruritic wheals that form after mast cell degranulation
- Characterized by superficial dermal edema and lymphatic channel dilation.
Strawberry Hemangioma and Cherry Hemangioma
- Strawberry hemangioma
- Benign capillary hemangioma of infancy
- Appears in first few weeks of life (1/200 births);
- Grows rapidly and regresses spontaneously by 5–8 years old
- Cherry hemangioma
- Benign capillary hemangioma of the elderly
- Does not regress.
- Frequency increases with age.
Angiosarcoma
- Rare blood vessel malignancy typically occurring in the head, neck, and breast areas. Endothelial origin.
- Usually in elderly, on sun-exposed areas.
- Associated with radiation therapy and chronic postmastectomy lymphedema.
- Hepatic angiosarcoma associated with vinyl chloride (like in PVC pipes) and arsenic exposures. Also associated with Thorotrast exposures.
- Very aggressive and difficult to resect due to delay in diagnosis
- Usually asymptomatic, may have RUQ pain or may impinge on nearby structures; excellent prognosis with resection
Glomus Tumor
- Benign, painful, red-blue tumor, commonly under fingernails
- Arises from modified smooth muscle cells of the thermoregulatory glomus body
Pyogenic granuloma
- Polypoid lobulated capillary hemangioma that can ulcerate and bleed
- Associated with trauma and pregnancy.
Pemphigus Vulgaris
- Pathophysiology
- Autoantibodies against desmosomes
- Symptoms
- Flaccid Bullae on Skin
- Oral Mucosa Involvement
- Intraepidermal Acantholysis
- Fluid Loss
- Infection
- Nikolsky Positive
- Diagnosis
- Biopsy showing Autoantibodies
- Treatment
- IVIG and Plasmapheresis
- Oral Steroids
- Immunosuppressants
2 mins
