[Eritema pigmentado fijo secundario a AINE: Reporte de caso].

Background: Fixed erythema pigmento (FPE) is an allergic drug reaction, the pathophysiology of which is not exactly known. It is more common in women with location on the face. Clinical presentation: round or oval red-purple macule, well defined, with swelling, pain, itching, and burning. Diagnosis is clinical, oral chal- lenge is contraindicated due to possible severe reaction. On withdrawal of the drug, residual violaceous hyperpigmentation remains.

Case report: 34-year-old female diagnosed with allergic rhinitis and asthma. She received treatment with ibuprofen and cephalexin 1 month ago due to dental infection. For the past 2 weeks, she has presented dermatological lesions characterized by hyperpigmentation under the lower eyelids, accompanied by pain, burning, and itching. On physical examination, well-defined red-purple pigmentation was observed in both periocular regions. The challenge test is not justified, the clinical history is the diagnostic pillar. The indication is to stop the medication immediately and continue monitoring.

Conclusions: EPF is a drug reaction related to drug use. It creates a challenge for diagnosis due to poor knowledge of the characteristics of the dermatosis and poor clinical and pharmacological questioning. The EPF approach requires knowing the clinical characteristics of this dermatosis, making a differential diagnosis with other lesions and indicating the suspension of the responsible medication.