Recurrent postcoital fixed drug eruption caused by co-trimoxazole mimicking a sexually induced disease

Abstract

We report a case of a woman which had in 6-months three episodes of a recurrent postcoital skin eruption, each lasting for a few weeks. It seemed like a sexually induced eruption. She admitted to take only her permanent therapy that could not be connected to her skin signs. Thanks to her Health Insurance Card with the digital record of all the drugs she had received in the last two years it was possible to find out that she was intermittently taking co-trimoxazole in order to prevent an after intercourse urinary bladder infection. A good evidence of the patient's medication has a key role in the diagnosis of skin adverse drug reactions. Fixed drug eruption is a common adverse drug reaction and everyone prescribing a long term antibiotic prophylaxis should be aware of it.

Uncommon variants of fixed drug eruption

“…Generalised bullous fixed drug eruption Antibiotics 15,16 (metronidazole, trimethoprim sulfamethoxazole, rifampicin, ciprofloxacin, 17 doxycycline and cefotaxime), analgesics (ibuprofen and naproxen), fluconazole, phenytoin, cetirizine, hydroxyzine, trazodone, 18 radio-contrast dye 19 and influenza vaccine 20 2. Post-coital fixed drug eruption Cotrimoxazole [40][41][42][43] and paracetamol 44 3. Fixed alcohol eruption Ethanol and annexing agents of spirits such as aliphatic and aromatic hydrocarbons 45 4.…”

“…Lesions can occur anywhere but typically involve the oral and genital mucosa. Drugs implicated are co-trimoxazole (oral [40][41][42] and local application 43 ) and paracetamol. 44 3.…”