Background: The prevalence of allergic disorders has been increasing over the last 30 years, especially in developed countries. One factor associated with this rise may be the decline of many childhood infections. We investigated tuberculin responses in allergic children in order to see the development of delayed-type hypersensitivity reactions to tubercule bacillus infection.
Methods: The study sample was composed of 106 allergic and 100 nonallergic children vaccinated with bacille Calmette-Guerin (BCG). The standard Mantoux test was applied to all children. The reactions were read after 72 h by measuring the diameter of the wheal.
Results: The wheal size was 6.29 ± 5.09 mm (mean ± SD) in allergic children, and 2.79 ± 2.96 mm in nonallergic children. The difference between the two groups was significant (P < 0.001). In children with a single BCG scar, the mean purified protein derivative (PPD) wheal size for allergic children was 4.77 ± 4.79 mm, and for nonallergic children it was 2.48 ± 3.19 mm. The mean PPD wheal sizes in allergic and nonallergic children who had been vaccinated twice were 8.35 ± 4.80 mm and 3.33 ± 2.44 mm, respectively. This difference was statistically significant (P < 0.05). In 27.35% of the allergic children and 6% of the nonallergic children, the positive tuberculin responses (PPD ≥ 10 mm) were recorded. The difference was significant (P < 0.05).
Conclusions: Our results showed that response to tuberculin in BCG-immunized allergic children is higher than in BCG-immunized nonallergic children.