Objective: To determine the prevalence of lactose malabsorption in young Lithuanian atopic dermatitis children; to evaluate the relationship between lactose malabsorption and the duration of exclusive breastfeeding, and the relationship between lactose malabsorption and cow's milk intolerance in parents and grandparents.

Methods: 144 children with atopic dermatitis aged 1.5-24 mo (study group) and 32 children without symptoms of allergic diseases aged 1.5-23 mo (control group) were investigated. Lactose and glucose-galactose absorption tests based on serial blood glucose determination, culture of stool, latex agglutination test for rotavirus and microscopic examination of stool for parasites were performed.

Results: Lactose malabsorption was determined in 59 (40.9%) and glucose-galactose malabsorption in 17 (11.8%) children with atopic dermatitis. The risk of developing lactose malabsorption was higher in children fed exclusively on breast milk up to 1 mo of age than in children fed exclusively on breast milk for 4 to 6 mo (OR: 2.62; 95% CI: 1.02-6.75). Lactose malabsorption was significantly more frequent in patients whose mothers did not tolerate cow's milk (20/30; 66.7%) than in patients whose mothers were tolerant to it (39/95; 41.1%) (p = 0.02).

Conclusions: Lactose malabsorption was determined in 40.9% of Lithuanian atopic dermatitis children aged under 2 y. Lactose malabsorption appeared to be associated with the duration of exclusive breastfeeding up to only 1 mo and mothers' milk intolerance.