Understanding the concept of ‘family history’ in black asthmatic children

Abstract

Background. Despite the fact that 71.6% of children at Chris Hani Baragwanath Hospital (CHBH) Asthma Clinic in Soweto, Johannesburg were found to have one or more positive skin-prick tests (SPTs) to common aero-allergens, they reported a low rate of positive family history for atopic conditions (22.2%). In the past this has minimised the importance of family history in determining the nature of chest symptoms in children in this population group, suggesting that some new environmental exposure, rather than the established familial factor, was creating the allergic milieu in this group.
Objective. To determine the predictive value of a family history of symptoms of atopic disease (and allergy) by seeking evidence for this condition in the parents of asthmatic children attending the CHBH Children’s Asthma Clinic, and the reason(s) why a positive family history has been found so seldom in these children.
Methods. A random group of parents of the atopic asthmatic children attending the CHBH Children’s Asthma Clinic completed a detailed questionnaire regarding their atopic status. Skin-prick testing was performed.
Results. Fifty-four sets of parents and 15 single mothers were studied. Of the 48 atopic children, 37 (77%) had at least 1 parent with a positive SPT. Fifty-five per cent of mothers had a positive SPT, while 48% of fathers had at least 1 positive SPT. Seven of 69 mothers (10%) had a definitive diagnosis of asthma. Of these, 5 (71%) were SPT-positive. Only 3 of the fathers (5.5%) had asthma. All had positive SPTs. However, if all the symptoms suggestive of asthma, namely chronic cough or wheeze, were taken into account, the number of potential atopic fathers and mothers increased to 10 (19%) and 18 (26%) respectively.
Conclusion. Simple questioning for family history of atopic disease is therefore not a good predictor of atopy in offspring in this cohort of patients. In order to get maximal yield from this question, parents must rather be asked about specific symptoms suggestive of asthma and/or allergic rhinitis.