Drug- and medication-associated intertriginous desquamating eruptions
The lesion distribution limited to the back and diaper area in an elderly woman receiving a recently started systemic antibiotic is most consistent with a drug-induced intertriginous/flexural exanthema pattern such as symmetrical drug-related intertriginous and flexural exanthema (SDRIFE, formerly drug-related baboon syndrome). [1], [2] A secondary high-likelihood drug-induced diagnosis in this medication context is a fixed drug eruption (including generalized or atypical fixed drug eruption variants), which can present with erythema and subsequent desquamation. [3], [4]
Most likely ciprofloxacin-associated diagnosis
- Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE, drug-related baboon syndrome)
- SDRIFE is a delayed-type hypersensitivity drug eruption characterized by symmetric, sharply demarcated erythema in flexural/intertriginous sites, classically involving buttocks/perianal region and other skin folds, with absence of systemic involvement. [1], [2]
- SDRIFE is strongly associated with systemic drug exposure, with reports describing antibiotic triggers. [2]
- Published case reports describe ciprofloxacin-induced SDRIFE. [5]
Other likely drug-induced diagnoses to consider
- Fixed drug eruption (FDE)
- Fixed drug eruption is a drug-induced cutaneous reaction in which lesions can become erythematous and later show desquamation after drug exposure. [3]
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Ciprofloxacin is reported in the literature as a trigger of severe cutaneous adverse drug reactions, including erythema multiforme-spectrum presentations that overlap clinically with fixed-drug and other hypersensitivity phenotypes. [6]
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Erythema multiforme–spectrum drug eruption (including erythema multiforme major and related hypersensitivity phenotypes)
- Ciprofloxacin has documented associations with hypersensitivity mucocutaneous eruptions including erythema multiforme. [6]
Key diagnostic discriminator supporting SDRIFE over alternative drug eruptions
- SDRIFE diagnosis is supported by intertriginous localization (diaper/buttocks/perianal distribution), symmetry, and lack of systemic symptoms, which separates it from systemic severe cutaneous adverse reactions. [1], [2]
Medication-relevant differential narrowed by distribution (back + diaper area)
- Contact dermatitis from topical diaper products is less likely to be the primary explanation when lesions are temporally linked to systemic exposure and show a symmetric drug-eruption pattern in flexural areas. [1], [2]
- Severe cutaneous adverse reactions (e.g., SJS/TEN, DRESS, AGEP) are not the best fit for an eruption confined to back/diaper area without systemic features. [1], [2]
Most likely answer (ranked)
- SDRIFE (symmetrical drug-related intertriginous and flexural exanthema; drug-related baboon syndrome), most likely related to the systemic antibiotic exposure (including ciprofloxacin). [1], [2], [5]
- Fixed drug eruption (including generalized/variant forms) with post-lesional desquamation. [3], [4]
- Erythema multiforme–spectrum drug eruption. [6]