Relationship between Hashimotos thyroiditis and other collagen vascular diseases?
Hashimoto’s thyroiditis occurs with increased frequency in several collagen vascular diseases. It has been described in systemic lupus erythematosus, Sjögren’s, and rheumatoid arthritis, as well as mixed connective tissue disease, SSc, and polymyositis. The coexistence of multiple autoimmune conditions is thought to occur due to shared genetic predisposition. The prevalence of HLA-B8, DR3, and DR5 is increased in patients with Hashimoto’s thyroiditis and several other autoimmune conditions commonly associated with this disease. Any patient with a collagen vascular disease should be followed closely for development of hypothyroid symptoms. Alternatively, more than 50% of patients with Hashimoto’s thyroiditis may present with arthralgias and/or fibromyalgia-type symptoms, and antinuclear antibodies can be seen in 25% to 35% of patients, creating potential confusion with a primary rheumatic condition.
