Allopurinol desensitization

An allopurinol-induced fixed drug eruption was successfully treated by desensitization (SEDA-21,108). Allopurinol can uncover latent lichen planus (15). 

Hypersensitivity reactions to allopurinol occur in about 10-15% of patients. Desensitization with both oral and intravenous allopurinol has been successful (SEDA-17,114). In the... 

Tanna SB, Barnes JF, Seth SK. Desensitization to allopurinol in a patient with previous failed desensitization. Ann Pharmacother 1999 33(ll) 1180-3. 

Fam AG, Dunne SM, lazzetta J, Paton TW. Efficacy and safety of desensitization to allopurinol following cutaneous reactions. Arthritis Rheum 2001 44(l) 231-8. 

Melsom RD Familial hypersensitivity to allopurinol with subsequent desensitization. Rheumatology... 

The cutaneous reaction caused by allopurinol is predominantly a pruritic, erythematous, or maculopapular eruption, but occasionally the lesion is urticarial or purpuric. Rarely, toxic epidermal necrolysis or Stevens-Johnson syndrome occurs, which can be fatal. The risk for Stevens-Johnson syndrome is limited primarily to the first 2 months of treatment. Because the rash may precede severe hypersensitivity reactions, patients who develop a rash should discontinue allopurinol. If indicated, desensitization to allopurinol can be carried out starting at 10—25 fjbg/day, with the drug diluted in oral suspension and doubled every 3—14 days until the desired dose is reached. This is successjul in approjdmately half of patients. Oxypurinol is available for compassionate use in the U.S. for patients intolerant of allopurinol. The safety of oxypurinol in patients with severe allopurinol hypersensitivity is unknown it is not recommended in this setting. 

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