Dermatopathia Pigmentosa Reticularis: Report of a New Cases and Literature Review.

Dermatopathia pigmentosa reticularis (DPR) is a very rare autosomal dominant ectodermal dysplasia caused by mutations in keratin 14 and characterized by the triad of generalized reticulate hyperpigmentation, nonscarring alopecia, and onychodystrophy. We report two Saudi brothers with DPR that had normal hair shafts, as assessed by scanning and transmission electron microscopy.

What was known?

Dermatopathia pigmentosa reticularis is an autosomal dominant ectodermal dysplasia (due to KRT14 mutation) characterized by a triad of widespread reticular pigmentation, non-scaring alopecia and onychodystrophy. Other associated findings include adermatoglyphia, hypohidrosis or hyperhidrosis, palmoplantar hyperkeratosis, and acral dorsal nonscaring blisters.

Introduction

Dermatopathia pigmentosa reticularis (DPR) is a very rare autosomal dominant ectodermal dysplasia. DPR was first described by Hauss and Oberste-Lehn in 1958,[1] with <20 cases described in the literature. DPR results from mutations in the KRT14 gene located on chromosome 17.[23] DPR is characterized by the triad of generalized reticulate hyperpigmentation, nonscarring alopecia, and onychodystrophy. Additional symptoms and findings may include the absence of or decreases in dermatoglyphia, hypohidrosis or hyperhidrosis, palmoplantar hyperkeratosis, and acral nonscarring blisters.[456]

Case Report

The case of 14 and 11-year-old siblings, born out of a nonconsanguineous marriage and delivered through Caesarian section, presented with generalized reticulate pigmentation since birth as well as generalized sweating and recurrent blisters, mainly over the soles. Furthermore, they reported progressive hair thinning and abnormal nail growth. There was no history of any neurological, ophthalmological, hearing, or teeth abnormalities; family history was insignificant. The patients had normal physical, social, and mental development. Cutaneous examination revealed a generalized, reticulate hyperpigmentation over the ears, neck, trunk, and extremities [Figure 1]. In addition, there was prominent pigmentation over the palmar and sole creases [Figure 2], and they had darkly pigmented nipples. Some of their nails were dystrophic [Figure 3], and they had abnormal dermatoglyphics compared to their father's dermatoglyphics [Figure 4]. They had diffuse nonscarring alopecia. Oral mucosa and teeth were normal. Histopathology showed hyperkeratosis, basal layer hyperpigmentation with cytoplasmic vacuolization, interface dermatitis, and scattered melanophages within the reticular dermis [Figure 5]. Transmission electron microscopic study of their hair shafts showed the normal arrangement of the hair shaft layers, normal compact arrangement, and orientation of the keratinized fusiform cells of the hair shaft and normal morphology and distribution of melanin granules in the cortical and medullary cells [Figure 6]. Scanning electron microscopic study was normal for both patients.

Figure 1

Generalized reticulate and mottled hyperpigmentation

Figure 2

Reticulate hyperpigmentation over palmer creases

Figure 3

Onychodystrophy

Figure 4

Loss of dermatoglyphics (1: Dermatoglyphics for their father. 2 and 3: Dermatoglyphics for patients)

Figure 5

Histopathology showing prominent melanophages (H and E, ×200)

Figure 6

Diffuse nonscarring alopecia and transmission electron microscopic study of hair shaft

Discussion

DPR was first described formally by Hauss and Oberste-Lehn[1] in 1958. Reviewing the literature revealed that <20 cases of true DPR have been reported in the literature. Most of the cases were reported in Europe, and a few cases were reported in the USA and Asia; there was no race or sex predilection for DPR. The onset of the reticulate pigmentation of DPR usually occurs at birth or during early childhood, and the rest of its manifestations appear later.

DPR is characterized by the triad of generalized reticulate hyperpigmentation, nonscarring alopecia, and onychodystrophy. Many other dermatologic findings have been associated with this triad, which include absent or decreased dermatoglyphia, hypohidrosis or hyperhidrosis, palmoplantar hyperkeratosis, acral nonscarring blisters, diffuse or punctate palmoplantar hyperkeratosis, darkly pigmented nipples, mucosal pigmentation, digital fibromatosis, neurofibromas, and wiry scalp hair.[45678910]

Few extracutaneous manifestations have been reported in the literature, which include fine punctate superficial spots in the cornea, Salzmann's nodular degeneration of the cornea, and early-onset gastric carcinoma.[481112]

The histopathology of the reticulate pigmentation of DPR is not diagnostic, and the reported histopathological features include mild orthokeratosis, papillomatosis, heavily pigmented epidermis, liquefaction degeneration of the basal layer, dermal pigmentary incontinence, melanophages, interface dermatitis, and sparse, superficial perivascular inflammations.[1013] The microscopic examination of the hair shaft showed normal hair shafts,[13] as observed in our patients.

DPR and Naegeli–Franceschetti–Jadassohn syndrome (NFJS) are allelic disorders[14] and both result from mutations in the KRT14 gene located on chromosome 17q11.2–q21.[2315] Although DPR and NFJS have poorly developed dermatoglyphics, specifically reticulate hyperpigmentation of the skin, DPR has been distinguished from NFJS by the lifelong persistence of the skin hyperpigmentation, partial alopecia, and absence of dental anomalies.[15]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

What is new?

Dermatopathia pigmentosa reticularis characterized by diffused non-scaring alopecia. Transmission electron and scanning electron microscopic study in our patients showed normal hair shaft structures. To the best of our knowledge this is the first report of DPR in Saudi Arabia.