Fixed Drug Eruption Following Concurrent Ciprofloxacin and Metronidazole Therapy: A Dermoscopy-Assisted Diagnosis

Fixed drug eruption (FDE) is a dermatological manifestation characterized by well-circumscribed erythematous-violaceous lesions that recur at identical anatomical sites upon re-exposure to the offending medication. We present a 39-year-old male who developed symmetric erythematous-violaceous macules in bilateral axillary, inguinal, and popliteal regions within 48 hours of initiating concurrent ciprofloxacin and metronidazole therapy for acute infectious diarrhea. Physical examination revealed six well-demarcated, tender, pruritic macules without mucosal involvement or systemic manifestations. Dermoscopic examination demonstrated a homogeneous violaceous background with fine pigment granularity throughout all affected areas. Due to resource limitations in the private clinic setting, skin biopsy and definitive drug causality testing were not performed. Both antibiotics were discontinued upon recognition of the cutaneous reaction. Treatment consisted of systemic corticosteroids (prednisone 20 mg daily for seven days), oral antihistamines (desloratadine 5 mg daily), and topical therapy including fluticasone propionate 0.05% nightly and calamine-based emollients. Symptomatic improvement was achieved with initial emergency treatment. Near-complete resolution of erythema occurred by day nine with residual post-inflammatory hyperpigmentation at previously affected sites. This case highlights the diagnostic challenge when multiple potential culprits are administered simultaneously, and confirmatory testing is unavailable. Dermoscopy proved valuable as a non-invasive diagnostic tool when histopathology was inaccessible. This report emphasizes the importance of clinical vigilance when prescribing commonly used antibiotics and demonstrates the utility of alternative diagnostic approaches in resource-limited settings. Primary care physicians and dermatologists should maintain awareness of FDE presentations and counsel patients to avoid re-exposure to implicated medications.