Comparison of symptoms of influenza A with abacavir-associated hypersensitivity reaction

Differentiation between abacavir hypersensitivity and viral respiratory infections is problematic. Fifteen cases of abacavir hypersensitivity were matched to 30 controls with culture proven influenza A with no abacavir exposure. Rash was associated with hypersensitivity (odds ratio OR = 13.1, P = 0.02) as was the presence of nausea (OR = 30, P < 0.001), vomiting (OR = 17.1, P = 0.001) or diarrhoea (OR = 22, P < 0.001). The number of gastrointestinal symptoms was also predictive of hypersensitivity reaction (P < 0.001). Respiratory symptoms (cough, sore throat, or dyspnoea) were not associated with abacavir hypersensitivity (OR = 0.08, P = 0.001). Multivariate analysis confirmed the following associations for abacavir hypersensitivity: the number of gastrointestinal symptoms (OR = 8.6, P = 0.0032), cough (OR = 0.039, P = 0.02) and rash (OR = 16.9, P = 0.07). Abacavir hypersensitivity is strongly associated with gastrointestinal (GI) symptoms. Cough without GI symptoms is associated with influenza.