Medically reviewed by Daniel More, MD Pictures of hives, also known as urticaria, can help you to identify these raised, red, itchy bumps or welts. Causes include stress, infections, food or latex ...

Chronic urticaria differs from acute urticaria in characteristics and treatments. The chronic form is spontaneous or inducible, with the latter elicited by cold, heat, pressure, or other precipitants.

Chronic idiopathic urticaria is another name for hives with an unknown cause. They might be a sign of an allergic reaction. We provide pictures of the condition and some popular treatment options.

Thirteen of the 16 patients who developed delayed onset of urticaria after receiving the Pfizer-BioNTech or Moderna COVID-19 vaccine booster had no previous medical history of urticaria. Image ...