Def : superficial mild chronic infection of the skin Etiology :coryneobactriumminutissimum Site : feet, groins, axillae, and submammary areas, which mimics epidermal dermatophyte infections Predisposing factor : Obisity , DM occlusive clothing/shoes Anaemia Hyperhydrosis Increased humidity Erythrasma(Greek, "red spot")
Clinical picture : Subjective symptoms :
Non - itchy disfigurement
Mild irritation in the grion
Morphology : - Dry , slightly scaly yellowish brown patches with sharply defined irregular border
The border is not active
Localization : Flexures , axillae , inner aspect of the thighs , umbilicus Anal cleft , under the beast in obese females Bilatral
Erythrasma: groins Sharply marginated, brownish-red, slightly scaling macular patch on the medial thigh (infectious intertrigo) appears bright coral-red when examined with a Wood's lamp.
Erythrasma: webspaceThis macerated interdigitalwebspaceThe webspaceis the most common site for erythrasma in temperate climates
DD : intertrigo Pitryasisversicolar Taeniacruris : erythematous scaly patch with active border Seborrheic dermatitis Psoriasis Candidal dermatitis
Laboratory Examinations Wood'sLamp demonstration of the characteristic coral-red fluorescence DirectMicroscopy Negative for fungal forms on KOH preparation of skin scraping. In the webspaces of the feet, concomitant interdigitaltineapedis may also be present. Gram or Giemsa stains may show fine bacterial filaments. BacterialCulture Heavy growth of Corynebacterium. Staph aureus, group A strep, and Candida infection. In some cases, concomitant Pseudomonas aeruginosawebspace infection (feet) is also present. Diagnosis Clinical findings, absence of fungi on direct microscopy, positive Wood's lamp examination.
Treatment : General : Erythromycin 1gm daily for 2w , Local : local antifungal : e g Tolnaftatetwice daily for 2-3w Imidazole derivative cream twice daily for 2-3w Sodium fusidate ointment, Benzoylperoxide (2.5%) gel daily after showering for 7 days
Pitted Keratolysis (Keratolysis Sulcata) (PK) presents as defects in the thickly keratinized skin of the plantar foot with eroded pits of variable depth, caused by Kytococcussedentarius. AgeYoung adults & Sex Males > females Predisposing Factors as erythrasma K. sedentarius produces proteases which digest keratin. Skin Symptoms Usually asymptomatic. Foot odor, sliminess of feet. Uncommonly, itching, burning, tenderness. Often mistaken for tineapedis. Skin Lesions Crater-like pits in stratum corneum Involved areas are white when stratum corneum is fully hydrated Symmetric or asymmetric involvement of both feet
Pitted keratolysis: plantar The stratum corneumshows loss of keratinization with well-dermarcatedmargins, Pitted keratolysis: toePitted epidermis of an intertriginous toe, associated with hyperhidrosis
Abscess, Furuncle, andCarbuncle Def : abscessis an acute or chronic localized inflammation, associated with a collection of pus and tissue destruction A furuncle is an acute, deep-seated, red, hot, tender nodule or abscess that evolves from a staphylococcal folliculitis A carbuncleis a deeper infection composed of interconnecting abscesses usually arising in several contiguous hair follicles.
Etiology : Causativeorganism : staph aureus Predisposingfactors: Pressure ,friction ,irritation of skin in exposed areas and extensor surface Chronic S. aureuscarrier state (nares, axillae, perineum, vagina) Diabetes mellitus Obesity Poor hygiene & Bactericidal defects (e.g., chronic granulomatous disease) Chemotactic defects Hyper-IgE syndrome (Job's syndrome) HIV disease, especially MRSA infection
Clinicalpicture : Morphology :
Perifollicular , tender , hot nodules with erythematous surface within few days transformed into necrotic core (remnant of hair follicle )
Localization affect area contain hair follicles : face , neck , back , axilla , arms and anorectal region Symptoms : The lesion is painfull , throbbing pain . Fever , mild constitutional symptoms Carbuncles may be accompanied by low-grade fever and malaise.
Furuncle: S. aureus Soft-tissue swelling of the forehead with central abscess formation, nearing rupture Furuncles: S. aureusMultiple areas of folliculitisin the moustache extending to become furuncles
Carbuncle: S. aureusA very large, inflammatory plaque with pustules, on the neck. Infection extends down to the fascia and has formed from a confluence of many furuncles. Multiple furuncles: Multiple, painful ulcerated nodules on the buttocks of a 20-year-old male, occurring during hospitalization for ulcerative colitis.
DD : Acne vulgaris Bockhart impetigo Herpes simplex Sweat rash Treatment : Local measures : - hot compressing - pirecing the pointed surface to discharging pus - cleaning the area by local antibiotic - a void occlusive dressing 2. General : antibiotic as penicillin & flucloxacillin .