PIP: In developing countries skin disease prevalences may affect over 60% of the community and are often poorly managed. The impact of ineffective treatment of skin disease on family life in rural Mexico was investigated. In the community of Cayaco, a house to house questionnaire survey was conducted to study the distribution of skin disease and the use and cost of treatments. The diagnosis of skin lesions was validated by physical examination and in a separate random survey in 120 primary school children. Regression analysis was carried out. 380 households with 1528 people (713 males, 815 women) were surveyed, of whom 207 reported skin disease. 131 attended the outpatient clinic (41 males, 90 females). The commonest skin disease among them was pyoderma (27 patients), followed by scabies (26), pityriasis alba (23), acne (8), dermatophytosis (8), viral warts (8), and pediculosis capitis (8). 66 had other skin conditions ranging from urticaria (2) to scrofuloderma (1). 58 patients had more than one condition, a total of 189 dermatoses. Six conditions accounted for 102 of the dermatoses. 15 patients with scabies and 21 with pyoderma had received ineffective treatment over the previous six months at a mean cost of 66 new pesos and 136 new pesos, respectively. Many of the affected children had missed school: eight days for scabies (12 patients) and 15 days for pyoderma (10 patients). 68 of the 120 primary school children in the random survey had at least one treatable skin condition. In half of the households people had symptoms, and 57% of the children had at least one treatable skin disease. The mean total cost of ineffective treatment for the two commonest conditions over six months was a major financial burden on families where the mean daily wage was 15.2 new pesos. Both diseases are readily curable by eliminating scabies. In the area a new system of community dermatology is implemented with close collaboration between specialists and primary health care workers.