Cockroach hypersensitivity in asthmatics in Lagos, Nigeria.

BACKGROUND

Cockroach allergy occurs frequently in asthmatics in urban areas, where the level of cockroach infestation is usually high. The prevalence of cockroach allergy, as well as the effect of associated factors on cockroach sensitisation in Nigeria is largely unknown.

OBJECTIVE

To determine the prevalence of cockroach allergy in asthmatics in Lagos.

DESIGN

A prospective case-control study.

SETTING

Medical outpatient department of the Lagos University Teaching Hospital, Lagos, Nigeria.

SUBJECTS: Two hundred and two patients with confirmed bronchial asthma and one hundred non-asthmatic control subjects took part in the study.

INTERVENTION: The cockroach allergen was administered on all the subjects using skin prick technique.

MAIN OUTCOME MEASURES: The provocation of a skin reaction (wcal) fifteen minutes after administering the cockroach antigen.

RESULTS

Amongst the asthmatic patients 90 (44.6%) had positive skin tests to the cockroach allergen, compared to nine (9%) of the control subjects. There was a male preponderance of cockroach sensitivity amongst the asthmatic patients even though the difference between both sexes was not significant. Other highlights of the study included the fact that cockroach sensitivity was related to age, duration of asthma, nocturnal asthmatic attacks, frequency of attacks, and the levels of infestation. There was an insignificant relationship between cockroach sensitivity and the location of residences as well as the income status of the respondents.

CONCLUSION

There is the need for more studies on cockroach allergy in asthmatics in our environment.