Papillon-Lefèvre syndrome, also known as hyperkeratosis palmaris et plantaris or hyperkeratosis palmoplantaris, is a devastating dermatological disease characterized by a thickening of the stratum corneum of the skin on the palms of the hands and soles of the feet. In addition, some patients manifest excessive sweating (hyperhidrosis), the growth of fine body hair and the development of dirty-colored skin on the affected parts. Calcification of the falx cerebri of the dura mater, as well as other areas of the brain, have been reported. From a dental standpoint, young patients with Papillon-Lefèvre syndrome have juvenile or precocious periodontosis, with severe destruction of the alveolar bone in both deciduous and permanent dentitions. Bone loss has been observed as early as two years of age, with premature exfoliation of the teeth. There is usually gingival enlargement, gingival ulceration and the formation of deep periodontal pockets; but in some cases, there is no inflammatory reaction and only the periodontium of the secondary teeth is affected. This disease eludes all known forms of therapy and results in edentulousness after only a few years.