Background
Urticaria consists of blanchable, erythematous “wheals” secondary to vasoactive mediators, predominantly histamine release from mast cells. Wheals are usually transient, disappearing from one aspect of the body and reappearing in new areas, and almost always pruritic. Acute urticaria refers to a presentation of less than six weeks, otherwise the term chronic urticaria is used. Most cases are idiopathic, but known triggers include drugs, infections, foods and even certain physical factors (such as cold, heat and sunlight)1.
Hyperthyroidism results from an excess state of thyroid hormones caused by excess release and increased synthesis from the thyroid gland, or less commonly, from extrathyroidal sources. Excess thyroid release is often stimulated by specific antibodies, including anti-thyroid peroxidase (TPO), anti-thyroglobulin (Tg), and anti-thyroid-stimulating hormone receptor (TSHR) antibodies2. Graves’ disease, the most common cause of hyperthyroidism, is an example of an autoimmune disease where thyroid-stimulating antibodies activate thyroid-stimulating hormone receptors, leading to excess hormone release from the thyroid gland3.
Urticaria and autoimmune hyperthyroidism appear to share an aetiological relationship, although the exact mechanism remains ambiguous4. In this report we discuss a new case of urticaria presenting itself as a manifestation of hyperthyroidism, the pathophysiology to this link is explored and management strategies are discussed.