Successful drug desensitization in patients with delayed-type allergic reactions to anti-tuberculosis drugs

Objective To evaluate the outcomes of anti-tuberculosis drug desensitization. Methods This was a retrospective study. Inclusion criteria were as follows: age >18years, documented tuberculosis infection, a previous cutaneous allergic reaction to anti-tuberculosis drugs, and having undergone drug desensitization between January 2003 and March 2014. The definition of allergic reaction to anti-tuberculosis drugs included (1) a temporal relationship between drug use and the allergic reaction; (2) improvement in the allergic reaction after drug withdrawal; (3) recurrence of the allergic reaction after reintroduction of only the offending drug; and (4) absence of other causes. Results A total of 19 desensitization procedures were performed. The drugs used for these procedures were isoniazid (n=7), rifampicin (n=6), or ethambutol (n=6). Of note, severe allergic reactions (Stevens-Johnson syndrome (n=4), erythema multiforme (n=3), and drug rash with eosinophilia and systemic syndrome (n=1)) were included. All patients underwent resolution of the previous allergic reactions before desensitization. The median duration of desensitization was 18 days. The success rate was 78.9%. The allergic reactions following failed desensitization were not severe; most were maculopapular rashes. Conclusions The desensitization protocol for anti-tuberculosis drugs was associated with a high success rate, and the individuals who failed desensitization experienced mild allergic reactions.