Dermatitis herpetiformis is a gluten-sensitive skin disease with intestinal lesions and malabsorption symptoms less severe than those found in celiac disease. While several studies have shown the occurrence of osteopenia in celiac disease, bone mass and metabolism have never before been evaluated in dermatitis herpetiformis. Therefore, in 16 untreated patients, 16 sex- and age-matched untreated celiac patients, and 16 sex- and age-matched healthy volunteers, lumbar and femoral bone mineral density were measured and bone and mineral metabolism and nutritional status were evaluated. All these parameters were significantly altered in the two groups of patients and although the degree of these alterations was milder in patients with dermatitis herpetiformis than in celiac patients, the presence of subtotal villous atrophy in patients with dermatitis herpetiformis was associated with the presence of more severe alterations. Bone mineral density was significantly correlated with nutritional status, and patients showing bone loss were characterized by a body mass index lower than 20. Alterations of bone mass and mineral metabolism complicate dermatitis herpetiformis when severe intestinal lesions coexist. A low nutritional status may be predictive of the presence of bone loss.