2022 Volume 36 Issue 3 Pages 248-256
Urticarial vasculitis presents urticaria-like eruptions that typically last longer than urticaria with pruritus and burning sensation and resolve with residual purpura or hyperpigmentation. It histologically shows leukocytoclastic vasculitis that affects small vessels in the upper dermis, especially postcapillary venules. It is classified into hypocomplementemic urticarial vasculitis with a decrease in serum complement titer and normocomplementemic urticarial vasculitis with a reference range of serum complement titer. Complement activation by immune complex formation due to anti-C1q antibodies is assumed to be a pathogenic mechanism of hypocomplementemic urticarial vasculitis syndrome. Most pediatric cases with cutaneous vasculitis are diagnosed with IgA vasculitis, and childhood-onset urticarial vasculitis is thought to be rare. However, there are cases of urticarial vasculitis with a certain probability. In some childhood-onset urticarial vasculitis cases, it was reported that mutations in DNASE1L3 were identified and they concurrent systemic lupus erythematosus. Urticarial vasculitis may present extracutaneous symptoms such as chronic obstructive pulmonary disease that affects their prognosis, various types of glomerulonephritis, episcleritis, and conjunctivitis. It is necessary to distinguish it from urticaria, systemic lupus erythematosus, autoinflammatory diseases, and so on.
