Exacerbation of chronic urticaria in the course of house dust mite immunotherapy.

It has been hypothesized that the house dust mite (HDM) is an etiopathogenic factor in some cases of chronic urticaria. In addition, it seems that some patients suffering from HDM-induced respiratory allergy and concomitant chronic urticaria may additionally benefit from allergen immunotherapy, manifesting as remission or alleviation of the symptoms. In this report we describe a patient with a history of respiratory HDM allergy and chronic urticaria who manifested exacerbation of urticarial symptoms in the course of HDM immunotherapy. This observation may confirm previous studies, suggesting that in some cases of chronic urticaria house dust mite allergens are causative or deteriorating factors contributing to development of this disorder.