Introduction Epidemiological data suggest that a minority of asthma cases in Latin America may be associated with allergic sensitisation which could be explained by the effect of environmental factors. The aim was to explore the relationship between levels of IgE specific for allergens (asIgE), skin prick test responses (SPT) and recent wheeze and the effect of age and geohelminth infections on these associations.

Methods A case-control study was conducted among 376 children aged 7–19 yrs living in Afro-Ecuadorian rural communities in tropical Ecuador. Asthma cases were selected based on the presence of recent wheeze and controls as a random sample of those without symptoms by questionnaire. Atopy was measured either by asIgE or SPT. Geohelminth infection was determined by both eggs in stools and anti-Ascaris IgE.

Results There was a significant positive association between the markers of atopy and recent wheeze in the older (7–11 yrs) but not in the younger (12–19 yrs) age group. A positive association between anti-Ascaris IgE and wheeze was observed in both the younger (adj. OR 2.06, 95% CI 1.05 to 4.03) and the older age groups (adj. OR 3.00, 95% CI 1.37 to 6.56). Having SPT responses was significantly associated with wheeze among children with no active geohelminth infection (adj. OR 3.52, 95% CI 1.05 to 11.79), while this association was lost among children with active infection (adj. OR 1.59, 95% CI 0.72 to 3.54).

Conclusions The association between markers of atopy and wheeze increased with age. The results suggest modification of the relationship between SPT and wheeze by active geohelminth infections.