Fixed Food Eruption due to Quinine Contained in Tonic Water

Abstract

A 30-year-old man presented with erythema and erosion on the lips, hard palate mucosa, and glans for five days. He also had an erythematous patch on the dorsal aspect of the left hand and the right thigh. He presented with the same condition three times in 9 months. Fixed eruption was considered on the basis of the clinical findings. A histopathological examination of the left hand revealed liquefaction degeneration at the epidermal-dermal junction and necrotic keratinocytes in the epidermis consistent with fixed eruption. After a detailed inquiry, we suspected fixed eruption due to food. Open-patch tests with tonic water, avocado and coriander performed on the lip were all negative. A patch test of 1%-quinine performed on the lesion of the dorsal aspect of the left hand was positive. Thus, he was diagnosed with fixed food eruption (FFE) due to quinine. Quinine is often added to tonic water as a bitterness component. FFE stands for fixed eruption due to food and food additives, including quinine. A summary of previously reported cases suggests that quinine-induced FFE is more likely to occur on the lips and oral mucosa compared to FFE induced by other foods. It is necessary to suspect foods as the cause of fixed eruption if the patient has no particular history of drug intake.