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.