Quinine allergy causing acute severe systemic illness: report of 4 patients manifesting multiple hematologic, renal, and hepatic abnormalities.

Quinine is widely used for the common symptom of leg cramps. Quinine tablets require a prescription, but quinine and the product from which it is derived, cinchona, are also available without prescription. They are components of over-the-counter remedies for many common symptoms, of nutrition products, and of beverages such as tonic water and bitter lemon. Although quinine has been used for centuries, initially as an extract from the bark of the cinchona tree, allergic reactions to quinine can be severe and can affect multiple organs. These allergic reactions can cause thrombocytopenia, neutropenia, anemia, disseminated intravascular coagulation, acute renal failure, liver toxicity, and neurological abnormalities. Because quinine use is often intermittent, defining quinine as a cause of an acute disorder may be difficult. Moreover, since quinine use is often self-regulated, patients may not mention it in response to direct questions about medication use, adding to diagnostic difficulty. The diversity and severity of quinine-associated disorders and the difficulties of diagnosis are illustrated by the presentation of 4 case histories. Awareness of the variety of potential quinine-associated reactions is important for accurate diagnosis and critical for prevention of recurrent illness.