Late Onset Progressive Symmetric Erythrokeratoderma with Pseudo Ainhum.

Sir,

A 44-year-old male born of nonconsanguineous parentage presented with asymptomatic, nonmigratory, polycyclic, hyperkeratotic scaly skin lesions on the extremities, trunk, and face for 3 years. The lesions initially started on chest, lower abdomen, and then eventually spread to involve the back and extremities. The patient had thickening of palms and soles for 25 years and progressive constriction rings at the base of toes and fingers for 8 years that have caused autoamputation of the fourth and fifth toes of the left foot. Meanwhile, the patient was diagnosed as having psoriasis and was initiated methotrexate a year ago; during this treatment period, he had noticed intermittent intervals of remission which recurred after stoppage of the drug and seasonal variation. Family pedigree showed similar complaints with variable presentations [Figure 1].

Figure 1

Pedigree tree of affected members with varied clinical presentations are represented by asterisk and black squares, proband is indicated by an arrow

On examination, well-demarcated, hyperpigmented, scaly plaques were distributed symmetrically on the extremities, dorsum of hands and feet, elbows, knees, axilla, upper chest, lower abdomen and back, and forehead [Figure 2]. Palmoplantar keratoderma (PPK) with pseudoainhum formation was noticed in toes with loss of the fourth and fifth toes of the left foot. There were dystrophic nail plate in greater toes, longitudinal ridging, and longitudinal melanonychia of the right index finger [Figure 3].

Figure 2

Clinical features: (a-c) Well-defined hyperkeratotic plaques distributed over the forehead, trunk, abdomen, and symmetrically in polycyclic configuration over the upper extremities

Figure 3

(a) Palmar keratoderma (b) longitudinal melanonychia (c) autoamputed toes of the left foot: Fourth and fifth toes (d) pseudoainhum in the right toes (second, third, and fourth)

Histopathology showed marked hyperkeratosis, significant parakeratosis, acanthosis, church spire appearance, and a moderate mononuclear infiltration in the upper dermis [Figure 4].

Figure 4

(a-c) Marked hyperkeratosis with parakeratosis, acanthosis, church spire appearance, preserved granular layer with intercalating rete ridges, and mild mononuclear dermal inflammation in the upper dermis (a: H and E, ×10, b and c: H and E, ×100)

A diagnosis of progressive symmetric erythrokeratoderma (PSEK) was made clinically which was consistent with the histopathological report. He was advised topical emollients, keratolytics, and started on acitretin 0.5 mg/kg body weight for a month; later, due to nonaffordability of this drug by him, he was started on isotretinoin 20 mg daily. There was a marked improvement in skin lesions at 6 weeks [Figure 5].

Figure 5

(a and b) Well-defined hyperkeratotic polycyclic plaques over the lower back at 0 week (c) Complete resolution of the lesions after the initiation of oral retinoids at 6 weeks

The original description of PSEK (OMIM 602036), by Darier in 1911, was entitled, “Erythrokeratodermie Verruqueuse en Nappes, Symmetrique et Progressive,” but the present name was given by Gottron in 1922.[1] It is a genodermatosis, predominantly autosomal dominant in inheritance, although autosomal-recessive transmission has also been observed with marked intra- and inter-familial variability of expression with <100 cases reported worldwide, among which <10 were from India.[2] In about 50% of the patients, positive family history can be obtained and rest of the cases are due to spontaneous insertional mutation in loricrin gene, and a recent report has also demonstrated connexin mutations in a PSEK patient.[23] PPK is seen in about 50% of the patients of PSEK, especially loricrin keratoderma, which is characterized by pseudoainhum formation.[4] PSEK is reported to be associated with high-arched palate, fissured tongue, pectus excavatum, symmetric syndactylism, and keratosis pilaris, cortical cataract, delayed intellectual milestones, mental retardation, narcolepsy, nephrotic syndrome, and convulsions have been reported.[45]

Topical retinoids, keratolytics, steroids, and calcipotriol show limited improvement while oral retinoids are more promising in treating PSEK.

In this patient, PPK lesions developed initially, nearly a decade later pseudoainhum, and eventually PSEK of late onset. The pedigree also showed varied phenotypic manifestations in siblings and relatives. Misdiagnosis and methotrexate intervention had partially changed the course of PSEK, thus pointing the need for complete clinical evaluation to confirm the final diagnosis.

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Conflicts of interest

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