Differential effects of age and intestinal helminthiasis on positivity rate of skin prick reaction to environmental allergens among Nigerians

Abstract

Background: Skin prick testing (SPT) conventionally used to investigate immediate type (type 1) hypersensitivity to allergens is reported to be affected by varying factors. It is hypothesized by present study that immunomodulation of T-cell by parasitic helminthic infection may affect skin prick reaction.Study Objectives: The primary objective of this cross-sectional study is to determine the prevalence of intestinal helminthiasis and its effect on the outcome of SPT to environmental allergens.Participants, Materials and Methods: Skin prick test was performed on 296 residents (113 adults and 183 children) rural and urban parts of Ibadan, South-West Nigeria. Stool specimen was also collected and examined for ova, cyst and larvae of intestinal worms.Results and Conclusion: The prevalence of intestinal helminthiasis was 20.8% and 21.2% in children and adults respectively. Prevalence of intestinal helminthiasis in adults from rural settings was significantly higher when compared with adults from urban settings. Significantly higher positive skin test to dog allergen was observed in helminth infected participants when compared to uninfected participants. Furthermore, significantly higher positive skin test to cockroach, mite, mold, and mouse allergen was observed in adults when compared to children. This suggests that the intestinal helminthiasis is found among all age groups in this region, but do not affect skin reaction to environmental allergens as much as ages of participants.