D2.32 - A Positive Drug Challenge to Amoxicillin and Clavulanate (AMX) in a Child, Six Years After the Initial Symmetrical Drug-Related Intertriginous and Flexural Exanthema (SDRIFE)

Background: Patient labeled “penicillin allergic” often receive non-beta-lactam (BL) antibiotics, specifically vancomycin or quinolones. The persistence of SDRIFE in a patient with low PEN-FAST score and tolerance to other BLs is not well established.

Method: We present a ten-year-old Asian girl who, at the age of four years, had the history of non-blistering red patches on waist, axillae, and groin, 1-2 hours after taking the first dose of AMX. No other systemic symptoms. Symptoms resolved spontaneously after 3-4 days. Patient has had the history of urticaria/dermatographism but otherwise healthy.  She has not taken beta-lactam antibiotics since.  Testing and drug challenge have been performed.

Results:

Prick skin test (ST), intradermal ST with immediate and delayed readings (24, 48, 96 hours), using the published nonirritating concentration were performed to penicillin G, AMX, cephalexin, ceftriaxone, cefdinir (prick ST only). Results were negative. After obtaining consent, patient underwent drug challenge to AMX (600/42.9 mg/5 ml) 0.8 ml, 2.5 ml, and 8 ml, every 20-30 mins and was observed for 2 hours without reactions. Five hours after the challenge, patient developed well-demarcated, burning erythematous rashes at groin, axillae and neck. There were no blisters, no mucosal lesions, no other systemic symptoms. Patient was seen in emergency room, given chlorpheniramine and methylprednisolone and admitted for observation. Lesions completely resolved at the follow up visit one week later.  Four months later an Enzyme linked immunospot (ELISpot) was done, yielding negative results to cephalexin, cefdinir and ceftriaxone.  A patch test at the location of previous rash was done to cephalexin and cefdinir with negative readings at 24 and 48 hours. Patient took single dose of 200 mg of cefdinir without reactions.

Conclusion:

We demonstrated that the SDRIFE due to AMX persists even after 6 years, despite low PEN-FAST score and negative delayed intradermal ST.  However, cefdinir (dissimilar R1 side chain from amoxicillin) is well tolerated. 

Consent for publication for this case report has been obtained from patient’s mother.