Safety and Low Incidence of Anaphylaxis in Performing Oral Drug and Food Challenges in Mastocytosis.

BACKGROUND

Patients with mastocytosis (MC) have an increased risk of severe anaphylaxis. They report hypersensitivity reactions to drugs and food, but causality often remains questionable. Most allergy centers avoid oral challenge tests (OCT) in MC patients.

OBJECTIVE

To determine the safety of food and drug OCT in patients with MC.

METHODS

To evaluate the safety and outcome of challenges to drugs and food including food additives retrospectively, of 126 adult MC inpatients, 83 were suspected to have food or drug hypersensitivity and 445 OCTs were performed. History, clinical data, and allergy test results highlighting OCTs were analyzed.

RESULTS

Only 10 of 445 OCTs (2.2%) in nine patients resulted in anaphylaxis. Drugs elicited reactions in four of 170 patients (2.4%): two to acetylsalicylic acid (two in 39 patients tested; 5.1%), one to tramadol (one in 12; 8.3%), and one to flurbiprofen (100%). Anaphylaxis to food was recorded in six of 275 OCTs (2.2%); two of 48 (4.1%) to galactose-α-1,3-galactose, two to other foods, and two to sulfites. Flushing or diarrhea occurred owing to histamine in five of 48 patients (10.4%), but also in five of 50 placebo challenges (10.0%), strongly questioning its relevance. Patients with proven anaphylaxis had more bone marrow MC and higher basal serum tryptase (71.3 vs 44.3 μg/L; P < .05).

CONCLUSIONS

Challenge-confirmed food and drug anaphylaxis was rare in MC patients. Results have to be interpreted cautiously because placebo reactions occurred. Severe anaphylaxis was infrequent but may occur and should be met by emergency preparedness.