Cockroach sensitivity in Norway: a previously unidentified problem?

BACKGROUND: Little is known about cockroach sensitization in Scandinavia, whereas cockroaches are implicated in allergic diseases throughout large parts of the world. In association with the Genetics of Asthma International Network (GAIN) study, we report sensitization to cockroaches and possible association with IgE-mediated diseases in Norway. METHODS: 100 Norwegian families (426 subjects) of 7-35-year-old sibling-pairs with asthma and their parents underwent questionnaire/interview (medical and exposure history), skin prick test (SPT) to common local inhalant allergens and German cockroach, and IgE specific to mites, mosquito, shrimp and cockroach. Cockroach sensitization was defined as positive if there was a positive (> or = 3 mm) skin prick test and/or presence of IgE antibody of class 2 or more. RESULTS: Thirty-one subjects (7.5%) were sensitized (five monosensitized) to cockroach (27 by skin prick test and seven by IgE antibody, all with additional inhalant allergy). Co-sensitization was most common to grass (in 61%), cat (48%), dog (48%) and mites (42%). Reported allergic diseases in cockroach-sensitized subjects were asthma and rhinitis (n = 10), asthma only (n = 9), rhinitis only (n = 2) and neither asthma nor rhinitis (n = 10). CONCLUSIONS: Since cockroach sensitization was relatively frequent in Norwegian atopic families, albeit with unclear clinical implications, we suggest that cockroach allergy should be considered in atopic subjects with respiratory disease.