Patients with chronic urticaria exhibit increased rates of sensitisation to Candida albicans, but not to common moulds.

Patients with chronic spontaneous urticaria (CU) frequently exhibit increased levels of total IgE (tIgE). However, sensitisations to relevant allergens are rarely detected in CU patients by standard prick testing suggesting that CU symptoms, at least in some patients, may represent hypersensitivity reactions to less common allergens. The objective of this study was to characterise skin reactivity and serum levels of IgE to Candida albicans (CA) and mould allergens in CU patients. A total of 112 CU patients and 35 healthy control subjects were subjected to intracutaneous skin testing for CA and seven ubiquitous moulds. Allergen specific and tIgE were determined using the Pharmacia CAP System. CU patients exhibited higher levels of tIgE than healthy subjects, but comparable rates of skin reactivity to CA and moulds and similar levels of specific IgE to mould allergens. However, increased IgE-anti-CA could only be detected in CU patients (13%). Almost all IgE-anti-CA positive CU patients showed high levels of tIgE. These data suggest that IgE-anti-CA expression contributes, at least in part, to increased tIgE levels in CU patients. Our findings call for further studies to characterise the relevance of CA hypersensitivity in CU, particularly in IgE-anti-CA positive CU patients that exhibit colonisation with Candida albicans.