Role of Inhalant Allergens in Atopic Eczema

The discovery that many patients with hay fever give immediate wheal and flare skin responses to extracts made from common environmental agents such as pollen, animal dander, of house dust was followed by testing of patients with other diseases [7]. Positive skin tests were found to be common not only in patients with rhinitis and asthma but also in patients with Besnier’s prurigo [4, 62]. The term atopic eczema (AE) was introduced by Coca and others, not only because the patients were atopic but also because they felt that these allergens played an important role in the pathogenesis of the disease. Reports were published showing that patients with food allergy and AE improved if they avoided the relevant food [25, 61]. In addition, Rost reported in 1932 [55] that patients with AE who were allergic to house dust improved often dramatically when they stayed in an “allergen-free room”. This observation was interpreted as showing that inhalants in the patients’ house were an important “cause” of AE. The view that allergen exposure was the major cause of AE was put very forcefully by Louis Tuft in a series of articles in the 1940s. His findings and views can be summarized as follows [64]: Positive skin tests to house dust from the patient’s house are very common in adults with AE (46 out of 54 cases). Children with AE are commonly allergic to foods, but by the age of 7 years they usually become allergic to inhalants, and these are the dominant allergens in adults. Adult patients not only improve when they are taken away from their houses but may also improve when their houses are cleaned. Finally, Dr. Tuft reported exacerbation of skin rash following nasal challenge with house dust.