Anaphylaxis is a severe systemic allergic reaction. Glucocorticoids rarely induce anaphylaxis. Determination of allergens includes the in vivo skin prick test (SPT) and intradermal skin test (IDST) and the in vitro basophil activation test (BAT). However, the usefulness of BAT in determining drug allergens has not been adequately studied.
A 10-year-old boy was admitted to our hospital because of fever and arthralgia for 2 weeks. He had not been treated with glucocorticoids. According to the laboratory tests and imaging studies, he was suspected to have bacterial myositis and was treated with ceftriaxone. However, his symptoms persisted for more than 2 weeks. With a suspicion of autoinflammatory arthritis, we planned methylprednisolone (mPSL) sodium succinate (MPS) during pulse therapy (30 mg/kg). Fifteen minutes after the injection of mPSL, he had wheezing and generalized wheal formation with decreased oxygenation. The administration of mPSL was discontinued because anaphylaxis was suspected. Thirty minutes after the administration of oxygen and oral olopatadine, the anaphylactic symptoms resolved.
One month after discharge, SPT, IDST, and BAT were performed under the administration of oral prednisolone. The SPTs for MPS, hydrocortisone sodium succinate (HCS) and prednisolone sodium succinate (PSS) were negative. The IDST for MPS was positive. Moreover, the IDSTs for HCS and PSS were positive, whereas those for dexamethasone sodium phosphate and betamethasone sodium phosphate were negative. The BAT for MPS was negative at 1.0% and 1.9% after an incubation time of 1 hour and 24 hours, respectively, although the BAT for histamine as positive control was 60.4% and 18.3% after an incubation time of 1 hour and 24 hours, respectively. The BATs for HCS and PSS were negative. Therefore, we diagnosed as anaphylaxis secondary to the succinate ester in MPS.
In this case, IDST was useful for the diagnosis of MPS-induced anaphylaxis, whereas BAT was negative. This highlighted the need to choose the appropriate procedure in the diagnosis of steroid-induced anaphylaxis. The results in our patient suggested that BAT may be considered when IDST and SPT are negative. Further studies are necessary to clarify the diagnostic strategy for steroid-induced anaphylaxis.