Hypersensitivity to levothyroxine in a substitutional therapy of Hashimoto syndrome

A 25-year-old woman was admitted to the Emergency Ward because of a severe allergic reaction. The clinical picture contained facial swelling, a rash of the face and neck (fig. 1.), skin itching and rumour, and dyspnoea with difficulties in swallowing. A detailed interview was collected, with particular emphasis on plausible allergens. The only substance that was new in the patient’s surroundings was the intake of levothyroxine according to Hashimoto syndrome, which was diagnosed a few days before. Given the suspicion of hypersensitivity to levothyroxine, the patient was admitted to the Clinic of Endocrinology. At first, the substitution of L-thyroxine was interrupted. Then, the preparation of L-thyroxine was changed to the liquid form and the patient started to take this under the observation of the ward’s medical personnel. After 5 days of novel preparation intake, no hypersensitivity reaction was observed – therefore the patient was discharged home with additional advice to attend the Allergology Ambulatory.