Differential Diagnosis

Case 1: Non-scaly papules A 27 yo call center agent complains of erythematous papules & nodules on the face especilally on the forehead, chin, cheeks & chin. She claims that she's had this problem since she was high school. Her elder brother had the same lesions.

Patient 27/FMiliaria Rubra ("heat rash", "prickly heat") retention of sweat as a result of occlusion of eccrine sweat ducts that produces an eruption Age of onsetsince high school persons of any age, but most common in infants Epidemiology hot, humid, tropical climates Etiology high heat and humidity Typical lesionerythematous papules & nodules discrete, extremely pruritic, erythematous papulovesicles Course days to weeks of exposure to hot environment Sites frequently affected on the face ( forehead, cheeks & chin) antecubital, popliteal fossae, trunk, inflammatory areas, abdomen, inguinal regions; face and volar areas are spared Management prickling, burning or tingling-like pain Patient 27/FMiliaria Rubra ("heat rash", "prickly heat") retention of sweat as a result of occlusion of eccrine sweat ducts that produces an eruption Age of onsetsince high school persons of any age, but most common in infants Epidemiology hot, humid, tropical climates Etiology high heat and humidity Typical lesionerythematous papules & nodules discrete, extremely pruritic, erythematous papulovesicles Course days to weeks of exposure to hot environment Sites frequently affected on the face ( forehead, cheeks & chin) antecubital, popliteal fossae, trunk, inflammatory areas, abdomen, inguinal regions; face and volar areas are spared Other clinical features prickling, burning or tingling-like pain Management controlling heat and humidity; removal of occlusive clothing, lots of fluids and cooler environment

Patient 27/F Scabies (“the Itch”) Sarcopetes scabiei (itch mite) Age of onsetsince high school persons of any age Epidemiology egalitarian; crowded and unhygienic living conditions Etiology skin-to-skin contact with an infected person, contaminated linens Typical lesionerythematous papules & nodules pruritic papular lesions, excoriations and burrows Course previously exposed: 2-4 days no exposure: 4-6 weeks Sites frequently affected on the face ( forehead, cheeks & chin) finger webs, wrists, axillae, areolae, umbilicus, lower abdomen, genitals and buttocks; scalp and face are spared Other clinical features intense pruritus (intense at night) women: itching of the nipples men: itchy papules on the scrotum and penis Management Permethrin 5% cream (Elimite)

Patient 27/F Insect Bites beetles, mites Age of onsetsince high school persons of any age Epidemiology mostly children and those who work outdoors Etiology insect bites Typical lesionerythematous papules & nodules Grain Itch: urticarial papule, intense pruritus Beetles: papulovesicular and urticarial dermatitis Course immediate Sites frequently affected on the face ( forehead, cheeks & chin) Grain Itch: trunk Beetles: chest, neck and forearms Other clinical features Pain, slight burning and tingling of the skin Management Antihistamines; calamine lotion

Patient 27/FAcne Vulgaris Chronic inflammatory disease of the pilosebaceous follicles Age of onsetsince high schoolbegins at puberty (15-18y/o) “disease of the adolescents” EpidemiologyAdolescent: M > F Not limited to adolescent 12% of women and 5% of men at age 25 years have acne By age 45 years, 5% of both men and women still have acne EtiologyHyperproliferation of keratinocytes Propionibacterium acnes Typical lesionerythematous papules & nodules characterized by comedone, papules, nodules, pustules, and even scars Course Sites frequently affected on the face ( forehead, cheeks & chin) affects face, neck, upper trunk and upper arms Managementtopical treatment - Topical Retinoids, Benzoyl Peroxide, Topical Antibacterials, Sulfur, Sodium Sulfacetamide, Resorcin, and Salicylic Acid, Azeleic Acid Oral antibiotics – tetracycline, erythromycin, clindamycin Other antibiotics – Sulfonamides, Trimethoprim- sulfamethoxazole, Trimethoprim, Dapsone

Patient 27/FFuruncles / Carbuncles Furuncles are skin abscesses caused by staphylococcal infection, which involve a hair follicle and surrounding tissue Carbuncles are clusters of furuncles connected subcutaneously, causing deeper suppuration and scarring; smaller and more superficial than subcutaneous abscesses Age of onsetsince high schoolYoung people EpidemiologyM > F EtiologyStaphylococcus infection Typical lesionerythematous papules & nodules nodule, pustule, or an acute, round, tender, circumbscibed perifollicular staphylococcal abscess Carbuncles = two or more confluent furuncles with separate heads Coursemost undergo central necrosis and rupture through the skin discharge purulent, necrotic debris; often continue for a prolonged period by autoinoculation Sites frequently affected on the face ( forehead, cheeks & chin) hair-bearing regions: beard area, nape, axilla, buttocks, but may occur anywhere Other clinical features carbuncles may be accompanied by fever and prostration ManagementWarm compress, Penicillinase-resistant penicillins, 1 st gen cephalosporin, Bactroban oinment, Incision and drainage

Furuncle Carbuncle

Patient 27/FPediculosis capitisPediculosis corporisPediculosis pubis infestation of lice -- blood-feeding ectoparasitic insects of the order Phthiraptera Age of onsetsince high schoolschool-age children (3-10 years old) EpidemiologyF > M Black race - rare M > F Adults > children EtiologyPediculosis humanis var. capitis (head louse) Pediculosis humanae var. corporis ( body louse) Phthirus pubis (crab louse) Typical lesionerythematous papules & nodules Erythematous macules, or urticarial wheals; Excoriated papules, parallel linear stretch marks; TransmissionHead-to-head contact (most efficient); Through inanimate objects will play (shared combs and brushes ) shared towels may play a role Sexually transmitted

Patient 27/FPediculosis capitisPediculosis corporisPediculosis pubis Sites frequently affected on the face ( forehead, cheeks & chin) scalpupper back; no involvement of hands and feet usually seen in the hairy areas of the vulva Other clinical features intense pruritus of the scalp; affected hair becomes dry and lusterless generalized itching; pigmented thickening of skin from continued scratching characterized by constant itching ManagementPermethrin Pyrethrins, combined with piperonyl butoxide Proper hygiene; Destruction of lice: Laundering the beddings and clothing, Disinfection Topical application of 1% Permethrin cream rinse (Nix) which is applied to affected area and wash off after 10 minutes; 1% Lindane shampoo (Kwell), applied for 4 minutes to affected area and subsequently washed off

Pediculosis Capitis Pediculosis corporis Pediculosis pubis