Mal de Meleda (MDM; also known as Meleda disease) is a rare hereditary diffuse palmoplantar keratoderma (PPK) with autosomal recessive (AR) inheritance. MDM is caused by a mutation in the SLURP-1 gene. SLURP-1 mediates keratinocyte apoptosis and down-regulates tumor necrosis factor-induced inflammation, and its loss of function leads to an inflammatory hyperkeratosis. The worldwide prevalence of MDM is estimated to be 1:100 000, with cases primarily located throughout Europe, Northern Africa, the Middle East, and southern Asia. Consanguinity is the greatest risk factor for disease.

Disease onset typically occurs within the first months of life. Bilateral diffuse erythema of the palms and soles is followed by development of palmoplantar hyperkeratosis with distinct yellow hue and well-defined margins. Severity increases with age. Hyperkeratotic plaques extend to the dorsal surface of the hands and feet (transgrediens pattern), are prominent over the knuckles, and may involve the lower legs. Psoriasiform or lichenoid plaques often appear on the knees and elbows, and perioral erythema may be observed. Nail involvement and disfigurement of the hands and feet are common, including pachyonychia, onycholysis, koilonychia, brachydactyly, conical tapering of the digits, constricting rings, and contractures. Palmoplantar hyperhidrosis is frequently seen.

Common complications of MDM include malodorous interdigital maceration with associated painful fissures and secondary infection. A very small number of cases of melanoma developing in involved skin of MDM have been reported.

Gamborg-Nielsen type PPK (PPK-GN) is now considered to be a mild variant of MDM as the conditions share a causative genetic defect. In PPK-GN, there is no nail involvement or hyperkeratosis extending beyond the hands and feet.