Comparative mites and cockroaches sensitization study in three cities of Mexico

In Mexico there are few research papers dealing with mites and cockroaches sensibilizing in patients suffering from respiratory allergies and even less susceptibility comparative studies to the same between cities having different climatic and geographic characteristics.

To research in a prospective study skin sensibilizing to eighy different mites and two cockroaches species in patients with respiratory allergies in three cities of Mexico: Monterrey, NL, Tampico, Tamps., and Irapuato, Gto., in order to determine if there are sensibilizing differences due to climatic and geographic conditions.

Skin tests were performed by scarification in 58 patients suffering diverse respiratory allergies such as bronchial asthma, allergic rhinitis, allergic rhinoconjunctivitis and combinations of the same. Tests were performed on 18 patients from Monterrey, 20 from Tampico and 20 from Irapuato. Mites used were: Dermatophagoides pteronyssinus, Dermatophagoides farinae, Blomia tropicalis, Tyrophagus putrescientiae, Lepidoglyphus destructor, Euroglyphus maynei, Acarus siro, Dermatophagoides microceras and 2 cockroaches species, Periplaneta americana and Blatella germanica.

Of the total 58 patients, the most important and frequent reactions were produced by D. pteronyssinus, D. farinae and E. maynei, which were found in 40, 33 and 32 patients respectively, then D. microceras in 21 patients, A. siro in 18, and B. tropicalis in 13 patients. In Tampico, the mite with the most frequent susceptibility was E. maynei, in Monterrey and Irapuato the most relevant were D. farinae and D. pteronyssinus, respectively. In Tampico, B. tropicalis was positive in 8 patients vs only 4 in Monterrey and 1 in Irapuato. The skin response to cockroaches was not important and the city with most positives was Irapuato with 6 patients responding to B. germanica, and 3 to P. americana; in Tampico 5 patients reacted to P. americana and 3 to B. germanica, and in Monterrey skin reactivity was slight and only 2 patients reacted to P. americana and 1 to B. germanica. Only 2 patients out of 58 in the study resulted in negative skin tests to mites and cockroachs allergens.

Only 2 patients out of 58 in the study resulted in negative skin tests, which demonstrates the high sensibilizing capacity from mite and cockroach allergens in patients suffering from respiratory allergies. Although the patient group is small, it reveals that mites from the Pyroglyphidae families D. pteronyssinus, D. farinae and E. maynei are the most sensibilizing in the three cities under research, without regards of geographic and climatic conditions as they were the most frequent skin reactants and produced greater skin symptoms in patients, with several differences in respect to skin reactivity, as they were greater in Monterrey than Tampico and Irapuato. Although there is crossed reactivity between mites of the Pyroglyphidae family, it might be convenient to routinely include E. maynei in the skin test panel practiced to patients with respiratory allergies in the cities under research, and maybe also B. tropicalis in Tampico. In comparison with mites, cockroaches produced little skin reactivity in the patients.