Diagnosing atopic dermatitis in infancy using established diagnostic criteria: a cohort study.

BACKGROUND: Diagnosing atopic dermatitis (AD) in infants is challenging. OBJECTIVES: To determine the incidence and persistence of eczema and AD in infants using the UK Working Party (UKWP) and Hanifin and Rajka (H&R) criteria. METHODS: A cohort of 1834 infants was examined clinically at 3, 6 and 12 months of age. AD was diagnosed by UKWP (3, 6 and 12 months) and H&R (12 months) criteria. Logistic regression models were used to assess the relationship between AD and eczema. RESULTS: Eczema was observed in 628 (34·2%) infants (n = 240, n = 359 and n = 329 at 3, 6 and 12 months, respectively), with AD diagnosed in 212 (33·7%) infants with any eczema and in 64/78 (82%) infants with eczema at all three visits. The odds of AD were lower with first presentation of eczema at 6 [odds ratio (OR) 0·33, 95% confidence interval (CI) 0·22-0·48] or 12 months (OR 0·49, 95% CI 0·32-0·74) than at 3 months, and higher in infants with eczema at three (OR 23·1, 95% CI 12·3-43·6) or two (OR 6·5, 95% CI 4·3-9·9) visits vs. one visit only. At 12 months, 156/329 (47·4%) fulfilled the UKWP and/or H&R criteria; 27 (8%) fulfilled the UKWP criteria only and 65 (20%) only the H&R criteria. Of the 129 infants who fulfilled the H&R criteria, 44 (34·1%) did not meet the itch criterion. CONCLUSIONS: Used in combination and at multiple timepoints, the UKWP and H&R criteria for AD may be useful in clinical research but may have limited value in most other clinical settings.

Filaggrin mutations in relation to skin barrier and atopic dermatitis in early infancy.

BACKGROUND: Loss-of-function mutations in the skin barrier gene filaggrin (FLG) increase the risk of atopic dermatitis (AD), but their role in skin barrier function, dry skin and eczema in infancy is unclear. OBJECTIVES: To determine the role of FLG mutations in impaired skin barrier function, dry skin, eczema and AD at 3 months of age and throughout infancy. METHODS: FLG mutations were analysed in 1836 infants in the Scandinavian population-based PreventADALL study. Transepidermal water loss (TEWL), dry skin, eczema and AD were assessed at 3, 6 and 12 months of age. RESULTS: FLG mutations were observed in 166 (9%) infants. At 3 months, carrying FLG mutations was not associated with impaired skin barrier function (TEWL > 11·3 g m-2  h-1 ) or dry skin, but was associated with eczema [odds ratio (OR) 2·89, 95% confidence interval (CI) 1·95-4·28; P < 0·001]. At 6 months, mutation carriers had significantly higher TEWL than nonmutation carriers [mean 9·68 (95% CI 8·69-10·68) vs. 8·24 (95% CI 7·97-8·15), P < 0·01], and at 3 and 6 months mutation carriers had an increased risk of dry skin on the trunk (OR 1·87, 95% CI 1·25-2·80; P = 0·002 and OR 2·44, 95% CI 1·51-3·95; P < 0·001) or extensor limb surfaces (OR 1·52, 95% CI 1·04-2·22; P = 0·028 and OR 1·74, 95% CI 1·17-2·57; P = 0·005). FLG mutations were associated with eczema and AD in infancy. CONCLUSIONS: FLG mutations were not associated with impaired skin barrier function or dry skin in general at 3 months of age, but increased the risk for eczema, and for dry skin on the trunk and extensor limb surfaces at 3 and 6 months.