Merck Manual

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Wingfield E. Rehmus

, MD, MPH, University of British Columbia

Reviewed/Revised Jun 2023
Topic Resources

Erythrasma is an intertriginous infection with Corynebacterium minutissimum that is most common among patients with diabetes and among people living in warmer climates. Diagnosis is clinical. Treatment is with topical antibiotics or oral clarithromycin.

Erythrasma in the groin manifests as irregular but sharply marginated pink or brown patches with fine scaling.

Erythrasma may also involve the axillae, submammary or abdominal folds, and perineum, particularly in obese middle-aged women and in patients with diabetes.

Diagnosis of Erythrasma

  • Clinical evaluation

Erythrasma fluoresces a characteristic coral-red color under a Wood light due to production of porphyrin by the causative bacterium. Absence of hyphae in skin scrapings also distinguishes erythrasma from tinea.

Differential diagnosis of perianal erythrasma includes perianal streptococcal cellulitis. Perianal streptococcal cellulitis causes pain and bright red erythema solely on perianal skin and lacks fluorescence on Wood light examination. Cultures for group A streptococcus done on skin swabs from affected children are positive.

Treatment of Erythrasma

  • Topical antibiotics

  • Oral clarithromycin

Topical erythromycin, clindamycin, mupirocin, fusidic acid, and benzoyl peroxide are effective for patients with localized erythrasma.

For patients with more extensive erythrasma, oral therapy with a single dose of clarithromycin 1 g or erythromycin 250 mg 4 times a day for 14 days is effective.

Recurrence is common.

If Wood light and potassium hydroxide (KOH) or fungal culture are not available to distinguish between erythrasma and superficial fungal infection, a combination of antibacterial and antifungal topical preparations should be considered.

Drugs Mentioned In This Article

Drug Name Select Trade
A/T/S, Akne-mycin, E.E.S., Emcin Clear , EMGEL, E-Mycin, ERYC, Erycette, Eryderm , Erygel, Erymax, EryPed, Ery-Tab, Erythra Derm , Erythrocin, Erythrocin Lactobionate, Erythrocin Stearate, Ilosone, Ilotycin, My-E, PCE, PCE Dispertab , Romycin, Staticin, T-Stat
Cleocin, Cleocin Ovules, Cleocin Pediatric, Cleocin T, CLIN, Clindacin ETZ, Clindacin-P, Clinda-Derm , Clindagel, ClindaMax, ClindaReach, Clindesse, Clindets, Evoclin, PledgaClin, XACIATO
Bactroban, Centany, Centany AT
Acne Medication, Acne-10, Acneclear, Benprox , Benzac AC, Benzac W, Benzac-10, Benzac-5, Benzagel, Benzagel-10 , Benzagel-5, BenzaShave, BenzEFoam, BenzEFoam Ultra , BenzePrO, Benziq, Benziq LS, BP Cleanser, BP Cleansing Lotion, BP Foaming Wash, BP Gel, BP Topical , BP Wash, BP Wash Kit, BPO, BPO Creamy Wash, BPO Foaming Cloth, Brevoxyl-4, Brevoxyl-8, Clean&Clear Persa-Gel, Clearplex , Clearplex X, Clearskin, Clinac BPO, Del Aqua, Delos, Desquam-E, Desquam-X, EFFACLAR, Enzoclear, EPSOLAY, Ethexderm BPW, Inova Easy Pad, Lavoclen-4 , Lavoclen-8, NeoBenz Micro, NeoBenz Micro Cream Plus Pack, NeoBenz Micro SD, NeoBenz Micro Wash Plus Pack, Neutrogena Acne Cream, OC8, Oscion, Pacnex, Pacnex HP, Pacnex LP, Pacnex MX, PanOxyl, PanOxyl 10 Maximum Strength, PanOxyl 5, PanOxyl AQ, PanOxyl Aqua, PanOxyl-10, PanOxyl-5, PanOxyl-8, Peroderm, RE Benzoyl Peroxide , Riax, SE BPO, Seba, Seba-Gel, Soluclenz Rx , Theroxide, TL BPO MX, Triaz, True Marker Lintera, Zaclir, Zoderm Cleanser , Zoderm Cream, Zoderm Gel, Zoderm Redi-Pads , Zoderm Wash
Biaxin, Biaxin XL
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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