Résumé : Family history can provide important information about a patient's psychological status, and thus their disease risk. A multicentric case-control study on family dysfunction was performed on 59 patients with psoriasis (63.7%), atopic dermatitis (11.9%) or alopecia areata (25.4%), and 47 patients with minor skin problems (controls), all attending a dermatological clinic or a psychodermatological consultation. The mean age of subjects was 47.7 years in the cases and 48.8 years in the controls. Women represented 53% of cases and 62% of controls. Patients and controls frst completed the General Health Questionnaire (GHQ-12) and the Toronto Alexithymia Scale (TAS-20) questionnaire. The overall prevalence of anxiety and/or depression in cases was 43.3% (71.4% in atopic dermatitis). To collect the family history a genogram was built by the interviewer during a semi-structured interview. It can show dysfunction in the family, as it highlights alliances and ruptures, generational repetition of behaviours of dependence or vulnerability, and traumatic events. The mean (± standard deviation) genogram score was 6.7 ± 3.3 in the cases and 3.0 ± 2.4 in the controls (p < 0.001). The cases had three times the risk of having moderate family dysfunction compared with controls and 16 times the risk of having a severe family dysfunction. The genogram score was correlated with the severity of the disease as evaluated by the patient. In conclusion, family dysfunction may play an important role in the onset or the exacerbation of psoriasis, alopecia, and atopic dermatitis. © 2011 Acta Dermato-Venereologica.