Symmetrical Drug-Related Intertriginous and Flexural Exanthema (SDRIFE) Unfolded: Diagnostic Pitfalls and Psoriatic Confounders Among Flexural Dermatoses

Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) is an uncommon, symmetrical drug rash that impacts intertriginous areas without exhibiting systemic symptoms. Its occurrence in a patient with pre-existing flexural dermatoses such as inverse psoriasis can complicate diagnosis, as in our case, where the eruption was initially suspected to represent a psoriatic flare. We present a 53-year-old female with biopsy-proven inverse psoriasis who experienced a broad symmetrical erythematous rash in flexural areas after receiving amoxicillin-clavulanate treatment. Clinical assessment, histopathological results, and Naranjo scoring supported a diagnosis of SDRIFE. The case emphasizes diagnostic challenges arising from shared characteristics with conditions like candidiasis, acute generalised exanthematous pustulosis (AGEP), and inverse psoriasis. SDRIFE was preferred over the flare of inverse psoriasis due to lesion appearance, temporal correlation with drug exposure, and absence of systemic symptoms. Interestingly, previous flexural psoriasis might have contributed as a risk factor via barrier impairment or recall phenomenon. This case emphasizes the importance of increased clinical awareness and histological assessment in flexural lesions, particularly in individuals with pre-existing dermatoses.