Abstract:
RATIONALE: Asthma is said to be an atopic condition
and the presence of atopy is regarded as a surrogate
marker for determining asthma in a young child
with chronic respiratory symptoms. However some
local community findings have brought into question
the association between allergy and asthma. The primary
aim of this study was to document the prevalence
and nature of allergy sensitivities in a group
of asthmatic children attending a tertiary hospital in
Pretoria, South Africa: (i) to compare them to a group
of matched non-atopic children; and (ii) to compare
them for co-morbid conditions present in the asthmatic
children.
METHODS: A random sample of 100 children attending
the asthma clinic at Pretoria Academic Hospital
was included after obtaining parental consent and
patient assent. An age- and sex-matched control
group of 50 non-atopic children was included. Standard
allergen extracts (Alk Abelló) with negative and
positive controls were administered to all children.
Reactions were positive if the wheal was 3 mm
greater than the negative control at 10 minutes (for
inhalants) and the cut-points of Sporik were used to
determine positive food reactions. All atopic children
had asthma confirmed by airway hyper-responsiveness
on spirometry.
RESULTS: 45 asthmatic children had a positive skinprick
test (SPT). Sixteen per cent of control children
had a positive SPT. The most common inhalant allergen
was Bermuda grass (22%). Peanut allergy was
documented in 9% of the patients.
CONCLUSIONS: Atopy (positive SPT and known disease)
was demonstrated in only 45% of asthmatic
children. This is less than many reported international
studies and suggests that asthma must be associated
with other environmental exposures in some
areas of the world, including ours.
