Underlying health conditions

Some examples of health conditions that can cause hives include:

• viral infections, such as the flu, the common cold, glandular fever, or hepatitis B
• bacterial infections, such as some urinary tract infections and strep throat
• intestinal parasites, such as Giardia lamblia
• autoimmune hypothyroidism
• autoimmune conditions, such as rheumatoid arthritis, systemic lupus erythematosus, Sjögren’s disease, celiac disease, and type 1 diabetes
• any other condition that causes inflammation of blood vessels

Chronic hives may start as an autoimmune response, but the exact cause is unclear.