Palmar-plantar keratoderma of Unna Thost associated with atopic dermatitis: an underrecognized entity?

We report six cases of palmar-plantar keratoderma of Unna Thost (PPKUT) associated with atopic dermatitis. All had typical features of PPKUT with diffuse, yellowish thickening on the palms and soles with a well-defined erythematous rim of demarcation on the sides associated with palmar-plantar hyperhidrosis. The changes were obvious since birth or arose during early life, and were persistent. We believe that the association between the two disorders is not coincidental but an underrecognized entity that may shed light on the underlying pathogenesis of these two conditions.