Endocrine Abstracts

A 29-year-old lady with known autoimmune thyrotoxicosis (TPO 712 IU/ml) presented with an urticarial rash. She was on carbimazole. A diagnosis of drug-induced reaction was suspected and treated as such. Her carbimazole was discontinued. After a day of treatment with steroids and antihistamines, she experienced flushing, orthostatic hypotension and difficulty in breathing. She was treated for anaphylaxis with adrenaline on intensive care unit. A formal Dermatology opinion was provided the following day, when the diagnosis of idiopathic urticaria and angioedema (ICUA) was given. The patient was discharged shortly afterwards on oral prednisolone, loratidine and propylthiouracil. Vasculitis and hepatitis screens were negative and complement levels were normal. She has remained well.

This case illustrates the clinical overlap between presentations of ICUA and anaphylaxis. Previous observations have shown that the syndrome of thyroid autoimmunity and ICUA can be associated with a marked worsening of reactive airway disease. Possibly, mediators released may contribute to acute bronchospasm and associated respiratory symptoms. Symptoms of orthostatic hypotension and intolerance often present when least expected and should be pre-emptively considered to avoid confusion in treating systemic allergic reactions. Flushing is a frequent sign and differentiating from complaints commonly associated with allergic reactions, rosacea and endocrinopathies is helpful too.

ICUA is a well recognized but rare condition associated with autoimmune conditions such as Grave’s disease and can be precipitated by drugs such as Carbimazole, albeit most commonly has no precipitant. Urticarial angioedema has been reported before in patients with positive thyroid microsomal (TPO) or thyroglobulin antibodies. It has been speculated that it may have an autoimmune basis. Thyroid test dysfunction is certainly not enough to diagnose thyroid disease and thyroid antibodies should also be tested for in patients who present with urticarial angioedema. Awareness of the association may result in the identification of previously undiagnosed thyroid disease.