Mal de Meleda shares transgressive PPK and hyperhidrosis with the Nagashima-type keratosis, but MDM is much more severe than the Nagashima type. It usually involves perioral erythema and occasionally exhibits brachydactyly, nail abnormalities, and lichenoid plaques.
In general, MDM follows a progressive course throughout the lives of the patients and extends to the dorsal surfaces of the hands and feet.1 Constricting bands surrounding the digits are typical and occasionally result in spontaneous amputation,1,3 which has never occurred in patients with the Nagashima type. The Gamborg Nielsen type of PPK is a moderately severe form that is characterized by a thick hyperkeratosis,
distinctly demarcated from normal skin. It differs from the Nagashima-type PPK in that the dorsal aspects of the finger joints are covered by hyperkeratotic plaques and there can be constricting bands surrounding the fingers.22 Acral keratoderma can also easily be differentiated from Nagashima-type PPK by its specific clinical findings, which include striate hyperkeratinosis of the palms and soles, hyperkeratotic plaques over the dorsum of the hands and toes, and linear hyperkeratotic lesions over the Achilles tendon areas,
ankles, elbows, and knees. Another possible differential diagnosis is symmetrical lividities of the soles, a rare dermatosis of unknown etiology, characterized by hyperhidrosis and symmetrical, bluish-red plaques on the soles of the feet, but its predilection is not limited to areas of pressure or patterns of innervations.23 Its skin manifestations are usually localized to the soles, and involvement of palms is rare. Regarding the mode of inheritance in Nagashima-type PPK, 8 sibling cases have been reported.9,12,13,15- 19 One case originated from a consanguineous mating.14 So far, no inheritance to descendants of the affected patients or other family members has been reported, to our knowledge. These previously reported cases suggest that the mode of inheritance is autosomal recessive.