['Some reports have suggested that psoriasis and eczema are seldom found together. Knowledge of disease co-occurrence could lead to improved understanding of shared or opposing pathological mechanisms.', 'We sought to determine whether psoriasis and eczema could exist simultaneously and consecutively in the same individuals.', 'Skin examination data relating to 9,263 British children born during March 3rd to 9th, 1958 (the National Child Development Survey), were analysed for the co-occurrence of eczema and psoriasis.', 'Of 354 children with visible eczema at the ages of 11 or 16 years, 5 (1.4%) were also noted to have visible psoriasis, compared to 89 (1.0%) of 8,909 children who did not have visible eczema at 11 or 16 years. The relative risk of psoriasis in a case of eczema was 1.41, 95% confidence intervals from 0.58 to 3.46.'] Are psoriasis and eczema mutually exclusive diseases?