IGHE and asthma: It is difficult to estimate the true prevalence of AFAD in asthma due to a lack of studies comprehensively assessing fungal sensitisation, defined as either a skin prick wheal ≥ 3 mm larger than the diluent, or a value of IgE by Immunocap assay of ≥ 0.35 IU/L towards a fungal allergen or extract.