Exposure to cockroach has been reported to cause asthma in many parts
of the world. Although house-dust-mite is known to be the most importa
nt indoor allergen in Turkey, there are few data on the prevalence of
allergy to cockroaches. Therefore, we evaluated the prevalence of cock
roach sensitivity in asthmatic Turkish patients to see whether it is a
lso an important source of asthma in addition to house-dust mites. A t
otal of 206 patients demonstrating the characteristic features of asth
ma were included in the study. Sixty-three percent of the patients wer
e considered atopic, and 37% were found to be nonatopic by skin prick
tests. Mite allergens were the most common cause of indoor allergy (50
%), while cockroach sensitivity was detected in 25.7% of all the asthm
atics. Among all cockroach-sensitive patients, 70% were also positive
for mites. A female predominance was observed in cockroach-sensitive p
atients, as 44% of atopic women and 34% of atopic men had positive ski
n tests with cockroach allergen. The average duration of asthma was 7.
1+/-5.6 years in cockroach-sensitive asthmatics, and there was no diff
erence between groups in average duration of asthma (P>0.05). Mild, mo
derate, and severe asthmatics constituted 73.6%, 20.7%, and 5.7% of th
e cockroach-sensitive patients, respectively. These data indicate that
cockroach is also an important source of domestic infestation in Turk
ey Thus, it seems reasonable to suggest the need for cockroach allerge
n in the routine battery of inhalant skin tests in this geographic loc
ation. However, possible cross-reactivity with mites has to be taken i
nto consideration during the clinical evaluation of subjects with cock
roach sensitivity, especially in our patient population with such high
rates of house-dust-mite allergy.