Hand eczema in twins: a questionnaire investigation

Hand eczema in a population-based twin cohort of 6666 persons aged 20-44 ye ars was investigated by means of a questionnaire regarding skin symptoms on the hands and self- or physician-diagnosed hand eczema. Genetic influence was observed by significant differences between identical and fraternal twi ns regarding casewise concordance rate and correlations in liability under the threshold model. The casewise concordance rates were almost twice as hi gh in identical compared with fraternal twins in both sexes. By extension o f the threshold model a joint analysis could be performed, resulting in a h eritability estimate of 0.65. Tendencies towards stronger genetic influence for men and for younger individuals were present, but neither was statisti cally significant, No particular symptom pattern expressed especially stron g or weak genetic influence, Hereditary factors for hand eczema were observ ed despite a presumably substantial individual-specific environmental varia tion, The hypothesis that hereditary risk factors may play a significant pa rt in the development of hand eczema in the general population, when no ext reme environmental exposure exists, seems justifiable. The relevance of kno wn individual risk factors such as atopic dermatitis or contact allergy in relation to heredity remains to be analysed, The possible importance of age and temporal change also needs further consideration.