Reliance on erythema scores may mask severe atopic dermatitis in black children compared with their white counterparts

BACKGROUND: The prevalence of atopic dermatitis (AD) has been shown to be higher in London-born black Caribbean children than in their white counterparts, but little is known about the severity of the disease. OBJECTIVES: To carry out a longitudinal survey to investigate potential risk factors for AD severity in children. We report our findings in relation to differences in disease severity between white and black children and the effect of inclusion and exclusion of erythema scores on this comparison. METHODS: The recruited children were identified by their general practitioners (GPs) as having presented with AD, and the U.K. diagnostic criteria for AD were used to verify the diagnosis. Interview and clinical examination of children took place up to four times, 6 months apart. Each time, the same observer assessed AD severity using the SCORAD (SCORe Atopic Dermatitis) index. Potential risk factors and confounders were evaluated with a five-page questionnaire. Non-parametric tests were used for statistical analysis and the study participant remained the unit of the analysis. RESULTS: In total, 137 children (82 urban and 55 rural) were recruited, and each seen up to four times. This gave 380 observations (69% of an expected 548). The urban population contained 42 (51%) white children, 26 (32%) black children and 14 (17%) from other races. The rural population was entirely white. The 14 children from other races were completely excluded from the statistical analysis. The black children were all born in the U.K. On crude analysis, children with black skin showed a non-significantly lower risk of severe disease when compared with white children (odds ratio, OR 0.84; 95% confidence interval, CI 0.4-1.76; P = 0.65), while a highly significantly increased risk was found after adjusting for erythema score (OR 5.93; 95% CI 1.94-18.12; P = 0.002). The difference remained significant even after controlling for other potential confounders. CONCLUSIONS: Black children with AD are about six times more at risk of having severe AD than their white counterparts. GPs and dermatologists should note that erythema can be a misleading indicator of severity in black children. Difficulties of assessment due to skin pigmentation might mean that severe cases are not being detected and appropriately treated.