D2.243 - From Risk to Solution: Effective Desensitization in a Confirmed Delayed Hypersensitivity Reaction to Albendazole

Albendazole is a benzimidazole with anthelmintic and antiprotozoal activity against intestinal and tissue parasites, including hydatidosis. Echinococcosis is a parasitic disease caused by infection with larvae of certain types of tapeworms from the genus Echinococcus. This disease can cause serious complications if not treated properly. Diagnosis is made through imaging and clinical analysis, and treatment may include surgery and antiparasitic drugs, such as albendazole. Hypersensitivity reactions (HR) to albendazole have been reported rarely. These reactions can be classified as immediate or delayed, depending on the latency period. We report a successful desensitization (DS) procedure in a patient with a confirmed delayed HR to albendazole.

We present the case of a 59-year-old woman diagnosed with a complicated hydatid cyst who, after 1 month of treatment with albendazole, began to experience pruritus and a generalized macular rash with eosinophilia. A hypersensitivity study to albendazole was performed using epicutaneous tests with albendazole (1% and 5% in vaseline) and a lymphoblastic transformation test (TTL) An oral albendazole 12-step desensitization protocol was followed, starting with 0.001 mg and progressing at 15-minute intervals (Table 1). Blood tests were performed before, after, and one week after desensitization.Table 1.

Epicutaneous testing was negative, and the TTL with albendazole was positive. The patient received albendazole without incident and was able to continue treatment with 400 mg of albendazole every 12 hours. There was no elevation of liver enzymes or eosinophil levels after desensitization, which was well tolerated by the patient.

In our case, it was observed that rapid desensitization with oral albendazole proved to be effective and safe in the management of this delayed hypersensitivity reaction. This therapeutic approach could be beneficial for other patients with a history of suggestive delayed hypersensitivity reactions who require treatment for parasitic diseases. To our knowledge, there are only two cases reported in the literature in which patients underwent DS with this drug, but they involved immediate reactions, not confirmed by allergological studies.