Richard Honsinger

Quantitative assessment of exposure to dog (Can f 1) and cat (Fel d 1) allergens: Relation to sensitization and asthma among children living in Los Alamos, New Mexico

BACKGROUND Our objective was to identify the allergens associated with asthma among schoolchildren in an area of the United States where dust mite growth is expected to be poor. Los Alamos, N.M., was chosen because it has low rainfall and is at high altitude (7200 feet) making it very dry. One hundred eleven children (12 to 14 years old) from the middle school who had been previously classified according to bronchial hyperreactivity to histamine (BHR) were studied. METHODS Sera were assayed for IgE antibodies to mite, cat, dog, cockroach, Russian thistle, and grass pollen, with both CAP system fluoroimmunoassay (Kabi Pharmacia, Uppsala, Sweden) and conventional RAST. Allergens were measured in dust samples from 108 homes with two-site assays for mite (Der p 1 and Der f 1), cat (Fel d 1), dog (Can f 1), and cockroach (Bla g 2). RESULTS Concentrations of dog and cat allergens were elevated in almost all houses with pets but were also high in a significant proportion of the houses without pets. Levels of mite allergen were less than 2 micrograms/gm in 95% of the houses, and cockroach was undetectable in all but two of the houses. Among the 21 with BHR who had symptoms, 67% had IgE antibody to dog and 62% had IgE antibody to cat. For these allergens IgE antibody was strongly associated with asthma (p < 0.001). By contrast, the presence of IgE antibody to mite, cockroach, or grass pollen was not significantly associated with asthma. CONCLUSION The high prevalence of IgE antibody to cat and dog allergens among these children is in keeping with the presence of cat and/or dog allergen in most of the houses. Furthermore, sensitization (as judged by IgE antibodies) to cat and dog allergens was strongly associated with asthma. On the other hand, no clear relationship was found between sensitization or symptoms and the current level of allergen in individual houses. The results show that in this mite-and cockroach-free environment sensitization to domestic animals was the most significant association with asthma.

Mite, cat, and cockroach exposure, allergen sensitisation, and asthma in children: a case-control study of three schools

BACKGROUND The amount of allergen necessary to sensitise genetically “at risk” children is unclear. The relation between allergen exposure and asthma is also uncertain. METHODS To ensure a wide range of allergen exposures the data from case-control studies of asthma in children aged 12–14 years attending three schools in Los Alamos, New Mexico and Central Virginia were combined. Skin prick tests to indoor and outdoor allergens and bronchial hyperreactivity to histamine were assessed in children with and without symptoms of asthma. The concentration of mite, cat, and cockroach allergens in dust from the children’s homes was used as a marker of exposure. RESULTS Three hundred and thirty two children (157 with asthmatic symptoms and 175 controls) were investigated. One hundred and eighty three were classified as atopic on the basis of allergen skin prick tests and 68 as asthmatic (symptoms plus bronchial responsiveness). The prevalence and degree of sensitisation to mite and cockroach, but not cat, was strongly associated in atopic children with increasing domestic concentrations of these allergens. Asthma was strongly associated with sensitisation to indoor allergens (p<10-6) and weakly to outdoor allergens (p = 0.026). There was an association between current asthma and the concentration of mite allergen amongst atopic children (p = 0.008) but not amongst those who were specifically mite sensitised (p = 0.16). CONCLUSIONS The domestic reservoir concentration of mite and cockroach, but not cat, allergen was closely related to the prevalence of sensitisation in atopic children. However, the prevalence of current asthma had a limited relationship to these allergen measurements, suggesting that other factors play a major part in determining which allergic individuals develop asthma.

Significance of tartrazine sensitivity in chronic urticaria of unknown etiology

Of 38 patients with chronic urticaria of unknown etiology who were evaluated for food and drug additive sensitivity, 53% (20/38) had urticaria for 1 yr or more. Total eosinophil counts were not elevated in most patients, and the frequency of atopy was found to be similar to that in a general population. Of these 38 patients, 10 (26%) had a personal history of aspirin intolerance, but elimination of aspirin did not relieve the urticaria. In a double-blind crossover challenge with 0.22 mg of tartrazine and a control, tartrazine sensitivity was found in 8% (3/38) of patients with chronic urticaria and 20% (2/10) of patients with aspirin intolerance.

Allergy immunotherapy safety: location matters!

Allergy immunotherapy is a highly effective therapy that has been used in the treatment of allergic rhinitis, asthma, and venom allergy for over a century. Subcutaneous immunotherapy (SCIT) is currently the only US Food and Drug Administration approved form of allergy immunotherapy. In this commentary, we address the safety issues that surround the location of care of SCIT administration in a supervised medical facility versus in the home or other medically unsupervised facility. Although analysis of the data suggests that SCIT has an excellent safety profile, we believe that this safety is largely due to the safety measures that are implemented when SCIT is administered in a medically supervised setting with appropriate staff and equipment to immediately recognize and treat anaphylaxis. In the home or medically unsupervised setting, the preinjection health assessment may not be adequate and access to immediate emergency medical treatment is unlikely to occur. We strongly urge all health care providers to adhere to the current Allergy Immunotherapy Practice Parameter recommendations and that patients be appropriately assessed before and monitored after allergy immunotherapy injections in a medically supervised facility.