Unusual abacavir hypersensitivity reported - initially diagnosed as throat infection

An unusual presentation of abacavir hypersensitivity reaction is reported in the November 7^th edition of AIDS (now available online). The allergic reaction to abacavir closely resembled tonsillitis and was initially treated as such, and was accompanied by abnormal liver function.

The case involved a 37 year old woman, coinfected with HIV and hepatitis C. Seven days after starting a triple nucleoside regimen consisting of AZT, 3TC and abacavir, she developed a fever and sore throat which worsened over two days, requiring admission to hospital. Her condition then deteriorated further, with additional symptoms including weakness, headache, joint-pain, and dry cough. The patient’s temperature reached 104^oF and her lymph nodes became enlarged in the cervix and throat, suggesting a peritonsillar abscess. Liver enlargement was also noted, and the patient also had abnormal liver function tests.

Antiretroviral therapy was continued, and the woman was prescribed antibiotics. Her condition worsened.

On the third day of hospitalisation, suspicion of an allergic reaction to abacavir prompted doctors to discontinue treatment with the drug.

Within 24 hours the woman’s symptoms almost completely disappeared, and there was no further progression of liver dysfunction with liver function tests gradually returning to normal.

The investigators conclude, “this severe episode of hypersensitivity was probably caused by abacavir, because in spite of the infection-like clinical presentation of our patient, tests for infectious diseases were negative, and in particular we witnessed a dramatic improvement after the withdrawal of abacavir.”

Approximately a third of all cases of abacavir hypersensitivity involve respiratory symptoms. The investigators comment, “our observation is remarkable because of the unusual clinical presentation of hypersensitivity to abacavir mimicking severe pharyngolaryngeal infection with localized lymph node enlargement.”

Further information on this website

Abacavir - overview