Common Dermatological Conditions - Distribution and Morphology

 • Acne vulgaris - Face, upper back, chest - Open and closed comedones, erythematous papules, pustules, cysts

 • Rosacea - Blush area of cheeks, nose, forehead, chin - Erythema, telangiectases, papules, pustules

 • Seborrheic dermatitis - Scalp, eyebrows, perinasal areas - Erythema with greasy yellow-brown scale

 • Atopic dermatitis - Antecubital and popliteal fossae; may be widespread - Patches and plaques of erythema, scaling, and lichenification; pruritus

 • Stasis dermatitis - Ankles, lower legs over medial malleoli - Patches of erythema and scaling on background of hyperpigmentation associated with signs of venous insufficiency

 • Dyshidrotic eczema - Palms, soles, sides of fingers and toes  - Deep vesicles

 • Allergic contact dermatitis - Anywhere - Localized erythema, vesicles, scale, and pruritus (e.g., fingers, earlobes-nickel; dorsal aspect of foot-shoe; exposed ivy)

 • Psoriasis - Elbows, knees, scalp, lower back, fingernails (may be generalized) - Papules and plaques covered with silvery scale; nails have pits

 • Lichen planus - Wrists, ankles, mouth (may be widespread) - Violaceous flat-topped papules and plaques

 • Keratosis pilaris - Extensor surfaces of arms and thighs, buttocks - Keratotic follicular papules with surrounding erythema

 • Melasma - Forehead, cheeks, temples, upper lip - Tan to brown patches

 • Vitiligo - Periorificial, trunk, extensor surfaces of extremities, flexor wrists, axillae - Chalk-white macules

 • Actinic keratosis - Sun-exposed areas - Skin-colored or red-brown macule or papule with dry, rough, adherent scale

 • Basal cell carcinoma - Face - Papule with pearly, telangiectatic border on sun-damaged skin

 • Squamous cell carcinoma - Face, especially lower lip, ears - Indurated and possibly hyperkeratotic lesions often showing ulceration and/or crusting

 • Seborrheic keratosis - Trunk, face - Brown plaques with adherent, greasy scale; "stuck on" appearance

 • Folliculitis - Any hair-bearing area - Follicular pustules

 • Impetigo - Anywhere - Papules, vesicles, pustules, often with honey-colored crusts

 • Herpes simplex - Lips, genitalia - Grouped vesicles progressing to crusted erosions

 • Herpes zoster - Dermatomal, usually trunk but may be anywhere - Vesicles limited to a dermatome (often painful)

 • Varicella - Face, trunk, relative sparing of extremities - Lesions arise in crops and quickly progress from erythematous macules, to papules, to vesicles, to pustules, to crusted sites.

 • Pityriasis rosea - Trunk (Christmas tree pattern); herald patch followed by multiple smaller lesions - Symmetric erythematous patches with a collarette of scale

 • Tinea versicolor - Chest, back, abdomen, proximal extremities - Scaly hyper- or hypopigmented macules

 • Candidiasis - Groin, beneath breasts, vagina, oral cavity - Erythematous macerated areas with satellite pustules; white, friable patches on mucous membranes

 • Dermatophytosis - Feet, groin, beard, or scalp - Varies with site, (e.g„ tinea corporis-scaly annular plaque)

 • Scabies - Groin, axillae, between fingers and toes, beneath breasts - Excoriated papules, burrows, pruritus

 • Insect bites - Anywhere - Erythematous papules with central puncta

 • Cherry angioma - Trunk - Red, blood-filled papules

 • Keloid - Anywhere (site of previous injury) - Firm tumor, pink, purple, or brown

 • Dermatofibroma - Anywhere - Firm red to brown nodule that shows dimpling of overlying skin with lateral compression

 • Acrochordons (skin tags) - Groin, axilla, neck - Fleshy papules

 • Urticaria - Anywhere - Wheals, sometimes with surrounding flare; pruritus

 • Transient acantholytic dermatosis - Trunk, especially anterior chest - Erythematous papules

 • Xerosis - Extensor extremities, especially legs - Dry, erythematous scaling patches; pruritis



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