Diagnosis: Erythrasma
A 45-year-old male presents with a 3-week history of asymptomatic red-brown patches in the groin. Under Wood's lamp examination, the lesions exhibit a characteristic coral-red fluorescence, prompting further evaluation for a superficial bacterial infection.
A 45-year-old male presents with a 3-week history of asymptomatic red-brown patches in the groin. On examination, the lesions are well-defined and located in the intertriginous areas, with no associated scaling or crusting. Notably, the lesions fluoresce a coral-red color under Wood's lamp, which is a key diagnostic feature.Location: Intertriginous zones, primarily in the groin area.Color: Red-brown patches with well-defined borders.Fluorescence: Coral-red under Wood's lamp examination.Symptoms: Asymptomatic with no pruritus or discomfort.Additional findings: No evidence of secondary infection or systemic symptoms.
The patient reports that the lesions began approximately three weeks prior, initially appearing as small reddish spots that gradually enlarged. He denies any recent changes in personal hygiene or new products in the groin area. The patient has a history of diabetes mellitus but no family history of skin conditions. He has not attempted any topical treatments prior to this visit.Onset: Lesions began 3 weeks ago with gradual enlargement.Triggers: No known triggers; denies recent changes in hygiene products.Prior treatments: No topical or systemic treatments attempted.Medical history: History of diabetes mellitus, well-controlled.Social history: Works as a construction worker; no significant exposures reported.
Acute / First-Line ManagementTopical clindamycin: Apply twice daily for 2-4 weeks.Oral erythromycin: 500 mg orally four times daily for 7 days may be considered if topical therapy is ineffective.Hygiene measures: Advise daily washing and thorough drying of affected areas.Workup and Diagnostic ConfirmationWood's lamp examination: Characteristic coral-red fluorescence confirms diagnosis.Cultures: Skin culture may be performed if secondary infection is suspected.Microscopy: Scraping may reveal characteristic bacteria.Long-Term ManagementPreventive measures: Advise on maintaining dryness in intertriginous areas.Follow-up: Re-evaluate in 4-6 weeks to assess treatment response.Consider recurrence: Patients with diabetes may be at higher risk for recurrence; therefore, education on skin care is essential.
Intertrigo: Inflammation due to friction and moisture, often not fluorescing under Wood's lamp.Tinea cruris: Fungal infection presenting with scaling and often pruritic, may not fluoresce.Candida infection: Typically presents with satellite lesions and is often pruritic; KOH prep may reveal yeast.Psoriasis: Plaques may appear similar but usually have silvery scales and lack fluorescence.Seborrheic dermatitis: Often affects scalp and face, presenting with greasy scales, not typically found in the groin.Inverse psoriasis: May present in skin folds but usually lacks the characteristic fluorescence.Contact dermatitis: Presents with pruritus and may be associated with exposure to irritants or allergens.Folliculitis: Inflammation of hair follicles that may mimic superficial infections, typically not fluorescing.
High-Yield PearlsCoral-red fluorescence: Wood's lamp examination is critical for confirming the diagnosis.Asymptomatic presentation: Erythrasma often presents without pruritus or discomfort, distinguishing it from other dermatoses.Prevalence in diabetes: Patients with diabetes are at higher risk for erythrasma and recurrent infections.Topical therapy: Clindamycin and erythromycin are effective first-line treatments.Prevention: Emphasis on hygiene and moisture control is essential in preventing recurrence.Remember, a coral-red glow under Wood's lamp is a hallmark of erythrasma, guiding the clinician towards the correct diagnosis.
Tags: erythrasma, corynebacterium