Mite and cockroach sensitization in allergic patients from Caracas, Venezuela.

BACKGROUND

Mites and cockroaches are important allergen sources in most countries, especially in the tropics. They have been incriminated as the cause of the increased prevalence of inhalant allergen sensitization that has occurred in many areas of Latin America.

OBJECTIVE

To study the prevalence of sensitization to mites and cockroaches in allergic patients from Caracas, Venezuela.

METHODS

Patients who attended the allergy clinics of two medical institutions, one public and the other private, were skin tested with two mite (Dermatophagoides pteronyssinus and Blomia tropicalis) and six cockroach extracts (Periplaneta americana, Periplaneta fuliginosa, Periplaneta australasiae, Blattella germanica, Blattella orientalis, Supella longipalpis) by the skin prick method. The socioeconomic level of the patients was determined by a modification of the Graffar method.

RESULTS

Of the 176 patients included in the study, sensitization to D. pteronyssinus was present in 97.2% of the patients and sensitivity to B tropicalis in 91.6%, whereas skin prick test results to at least one cockroach extract were positive in 83.1% of the atopic patients. An increased sensitization rate to cockroach allergens was observed in patients from lower socioeconomic levels and those attending the public institution.

CONCLUSIONS

Because of the high sensitization rates observed in this study, we propose that mite and cockroach allergens are important inducers of symptoms in allergic patients in Caracas. People from low socioeconomic levels and those who live with inadequate hygienic conditions show higher degrees of sensitization to cockroach allergen.