THE APPEARANCE OF THE COCKROACH IN HOUSE DUST

Epidemiological and immunological studies now provide confirmation that the cockroach is an important antigenic constituent of house dust. Among the 3 500 species of cockroach, those most often found in our regions are the German cockroach (BG), the Oriental cockroach (BO) and the American cockroach (PA). These cockroaches are most often responsible for severe asthma, rhinitis, eczema and urticaria. The incidence of cutaneous sensitisation to cockroaches in allergic individuals is, on average, 12 per cent in Europe, 53 per cent in the USA and 46 per cent in Asia. The incidence of plasma sensitisation is generally lower than the cutaneous incidence. In the Paris area, we found cutaneous sensitisation to BG in 15 to 20 per cent of children with chronic respiratory disease. Cutaneous sensitisation to cockroaches came in sixth position after cutaneous sensitisation to Dermatophagoides farinae (61%), Dermatophagoides pteronyssinus (48%), three grasses (29%), cat (24%) and wheat (18%). Two major allergens are identified in BG extracts : Blag I and Blag II. Relative levels of Blag I and Blag II vary considerably according to species and extracts available on the market. The treatment of cockroach allergy is based above all on elimination of the insects from the environment and the symptomatic treatment of allergic manifestations. In order to be effective, the entire building must be treated when eliminating insects from multiple occupancy premises. Unfortunately, no legislation exists forcing the owner to carry out such measures when infestation exists.