Punctate palmoplantar keratoderma

Introduction

Palmoplantar keratodermas are a heterogenous groups of disorders characterised by abnormal thickening of palms and soles. Autosomal recessive, x-linked and dominant modes of inheritance as well as acquired forms have been described. Clinically three distinct patterns of palmoplantar keratodermas may be identified-diffuse, focal and punctate. We report a case of Palmoplantar Keratoderma-Punctate type.

Case Report

A 50-year-old male presented with multiple, diffuse hyperkeratotic papules on palms and soles since 30 years. They have gradually increased in number spontaneously and have been painful while walking. There was a family history of similar lesions, hypertension, diabetes mellitus and carcinoma.

On cutaneous examination multiple, punctate hyperkeratotic papules of a near uniform size of 0.5x0.5cm diameter were seen on plantar aspect of both feet including the lateral borders. Palms show hyperkeratosis and few papules. Mucosal surfaces were not involved. Patient had no systemic complaints.

Routine investigations, blood biochemistry, USG abdomen and x-ray chest were inconclusive. VDRL and ELISA for HIV were negative. Tissue analysis for arsenic was inconclusive. Eye examination showed a normal picture.

Histopathological examination of biopsy specimen showed hyperkeratosis, hypergranulosis, acanthosis, elongation of rete ridges and sparse dermal mononuclear cell infiltrate.

Compilation of clinical and laboratory data helped to conclude the diagnosis of Palmoplantar Keratoderma-Punctate type.

Discussion

Punctate keratoderma has failed to be identified as a clinical entity because of varied nomenclature and differing usage of related terms. Synonyms used in literature for punctate keratoderma are disseminated clavus of hands and feet, focal acral hyperkeratosis, hereditary painful callosities, keratosis punctata palmoplantaris, keratodermia palmoplantaris papulosa (Buschke-Fischer), porokeratosis palmaris et plantaris disseminata, punctate keratoderma of the palmar creases.[1]

Punctate keratoderma is an autosomal dominant disorder with equal sex incidence. Incidence reported is 1.17/100000. The onset of the condition is much later than the diffuse variety of keratodermas. Lesions usually appear in 2nd or 3rd decade. Hard keratotic papules appear on palms and soles which can be picked out easily leaving small pits. In contradistinction to diffuse keratodermas there is no associated hyperhidrosis.[1] Associated features are rare and can be spastic paralysis,[2] ankylosing spondylitis, anodontia, deuteranopia, deuteranomalia and freckle like hyperpigmentation on the dorsa of hands and feet. Coincidental and a possible familial association with gastrointestinal malignancy have also been reported.[3]

The possibility of a keratin gene mutation being responsible for this pattern of keratoderma has been excluded by linkage analysis. Other mechanisms than keratin mutations may also be responsible for punctate keratoderma.

Differential diagnosis considered include corns, calluses, secondary syphilis, AIDS associated keratoderma, Reitre′s syndrome, Bazex syndrome and arsenical keratoses.[4]

Prior to the advent of retinoids there was no satisfactory treatment for punctate keratoderma, but subsequent to their availability there have been reports regarding a variable response. Etretinate 0.5mg/kg.day produced good results in three patients, moderate in four while it failed in two patients.

In another study, acitretin was rapidly effective but did not induce complete regression of the lesions. Maintenance therapy was required to prevent relapse.[5]

This case is presented for its clinical rarity.