Skin sensitivity patterns to inhalant allergens in Nigerian asthmatic patients

The pattern of skin sensitivity response to inhalant allergens in 746 Nigerian asthmatics and 92 normal controls tested over 10 years period is reported. Significant differences in reactions were observed in 7 of the 16 allergens routinely used in the study. House dust mite--dermatophagoides pteronyssinus gave the highest incidence of positive skin reaction, 58% asthmatics, 4.3% controls (P < 0.001). Other significant allergens were house dust 51.7%, feathers 24.4%; dog hair 12.9%, cat fur 11.9%, grass pollen 6.8% and flower pollen 6.3%. More males than females reacted to most of the allergens but this was statistically significant only for feather (P < 0.02). There was good correlation between history and skin sensitivity for most allergens. 82.3% of patients with positive skin test to D. pteronyssinus gave positive history of dust induced asthmatic attacks. Similar results were obtained for pollens: grass (86.3%), flower (83%) and feathers (57.7%). The correlation was however poor in respect of normal allergens (dog 30.6%, cat 36%). From the findings of this study there may be no point in routinely testing patients with a battery of allergens most of which may have no importance in the tropics. Attempts are however underway to incorporate local substances in skin testing materials. It is hoped that the results of this study will assist doctors who may not have access to skin test reagents in management of their asthmatic patients.