Abstract / Summary
A previously healthy 4-year-old boy presented with progressive left eyelid swelling and erythema, without reported animal exposure. Initially diagnosed as impetiginized eczema, the lesion was treated with topical antibiotic and corticosteroid therapy. Due to early clinical worsening, this was subsequently escalated with oral amoxicillin–clavulanate (50 mg/kg/day) and azithromycin (10 mg/kg/day). However, this local and systemic regimen failed and worsened the clinical presentation over a 9-day period. Inflammatory markers and blood cultures remained normal. Due to outpatient treatment failure, an initial periorbital skin and ciliary margin swab was collected on day 9 of oral antibiotics. Two days later, worsening symptoms prompted hospital admission for intravenous broad-spectrum antibiotics (ceftriaxone and clindamycin) and fluconazole. Pending culture results, suspected vesicular lesions led to empirical oral acyclovir (20 mg/kg/dose, 4 times daily); this was discontinued after 3 days when the initial swab returned negative for HSV. Ultimately, after an 8-day incubation, the outpatient swab culture yielded Trichophyton mentagrophytes species complex. Following microbiological identification of the dermatophyte, antifungal treatment was optimized with systemic griseofulvin and topical terbinafine, leading to complete clinical resolution. This case highlights atypical periocular dermatophytosis masquerading as a refractory bacterial and viral infection. Since direct animal exposure was not reported and phenotypic identification alone cannot distinguish between zoophilic (T. mentagrophytes) and anthropophilic (T. interdigitale) subtypes, the exact source of infection remains undetermined. In conclusion, while ‘tinea incognito’ is well documented, this report illustrates an exceptionally atypical periocular manifestation that mimicked a refractory bacterial cellulitis and simulated a herpetic infection. The novelty of this case lies in its severe clinical mimicry—including the development of chalazion-like lesions—which confounded a multidisciplinary team and led to unnecessary systemic antiviral and broad-spectrum antibiotic therapies, strongly highlighting the clinical importance of considering dermatophytosis in atypical orbital presentations.