000587 - Generalized Acute Eosinophilic Folliculitis Induced by Drugs in an Oncology Patient

The occurrence of an adverse drug reaction in polymedicated patients represents a diagnostic challenge, particularly in severe reactions or when one of the potential culprits is an essential medication.

A 53-year-old female patient with stage IV lung adenocarcinoma and brain metastases undergoing treatment with osimertinib and levetiracetam for the past 8 months., She was prescribed a 3-day course of azithromycin for symptoms consistent with a common cold. Three days after completing the treatment, she developed a polymorphic cutaneous rash without mucosal involvement, clinically diagnosed as severe erythema multiforme. Laboratory tests revealed eosinophilia up to 890, without other abnormalities. Treatment with corticosteroids and antihistamines was initiated, but the cutaneous lesions persisted for 10 weeks, ultimately resolving with residual hyperpigmented lesions.During initial clinical evaluation, levetiracetam was substitutedwith valproic acid, achieving good seizure control. Osimertinib was continued due to its critical role in the patient´s treatment régimen and, and was well tolerated. Macrolides were subsequently contraindicated, as they were considered non-essential for this patient´s care.

-Skin biopsy: findings consistent with eosinophilic folliculitis.-Allergy testing: Prick test and intradermal reaction (IDR) with azithromycin and levetiracetam yielded negative immediate results. However, the IDR with azithromycin showed erythema, papules, and vesicles at 24 hours.Despite the contraindication, the patient took a single azithromycin tablet for a cold two years later. Twenty-four hours afterward, she developed a generalized papulovesicular rash that resolved with oral corticosteroids and antihistamines. A skin biopsy revealed ulcerated areas with a mixed inflammatory infiltrate.

-We present a case of generalized acute eosinophilic folliculitis,  also known as Ofuji, disease, triggered  by azithromycin. The diagnosis was confirmedthrough biopsy, skin testing, and an uncontrolled drug challenge.-The patient’s compromised immune status, secondary to her oncological condition and the use of a tyrosine kinase inhibitor, may have contributed to an uncommon adverse reaction not typically associated with drug hypersensitivity reactions.