Preferential Localization of Fixed Drug Eruption Over a Cosmetic Red Lip Tattoo.

Fixed drug eruption (FDE) is a delayed hypersensitivity reaction characterized by recurrent lesions at the same site following re-exposure to an offending medication. Preferential localization over tattooed skin is rare and may mimic tattoo hypersensitivity. We report a 27-year-old woman with recurrent burning, swelling, oozing, and progressive hyperpigmentation predominantly affecting cosmetically tattooed ("lip blushing") lips. Symptoms began approximately one year after tattoo placement and recurred intermittently. The patient reported episodic use of trimethoprim-containing medications, ibuprofen, and ciprofloxacin preceding several flares. During the most recent episode, a solitary hyperpigmented buttock patch developed. Examination revealed violaceous-gray hyperpigmentation involving the tattooed lips and a well-demarcated buttock patch consistent with healed FDE. The clinical course favored FDE preferentially localized to an immunologically altered cutaneous district created by cosmetic tattooing rather than tattoo hypersensitivity. This case highlights cosmetic tattooing as a potential locus minoris resistentiae that may predispose to preferential FDE localization and delay diagnosis.