Ashy dermatosis: a controversial entity.

We present here the case of a young Indian male with slowly progressive, diffuse darkening of the face, arms, neck, and trunk. The patient was not taking any medication and there was no history of any previous skin disease and the mucous membrane was not involved. These findings are consistent with a diagnosis for ashy dermatosis of unknown etiology.

Introduction

Ashy dermatosis is a hypermelanotic disorder of the idiopathic variety characterized by bluish-grey macules in healthy individuals.[1] It is a controversial entity and is sometimes considered as a variant of lichen planus.[2] Etiology of ashy dermatosis is mostly unknown and it usually affects the face, arms, neck, and trunk. Dark colored individuals are most commonly affected in their second decade of life. Ashy dermatosis usually has a symmetrical distribution but cases with unilateral presentation have also been observed.[3] Mucosal involvement is a rarity.[1] Lichen planus pigmentosus, occupational dermatosis with hyperpigmentation, drug-related dermatoses, universal acquired melanosis, and familial progressive hyperpigmentation are the common entities confounding diagnosis.

Case Report

Our case was a 20 year-old Indian male who presented with slowly progressive, diffuse darkening of the face, arms, neck, and trunk seen over the last two years [Figures 1 and 2]. The lesions were nonscaly and nonpruritic in nature. He had no previous history of skin diseases and was not on any kind of medication during this two-year period. The oral mucous membrane was not involved [Figure 3]. On examination, the patient was found to be active, alert, and healthy. Laboratory investigations suggested normal blood counts, blood glucose level, normal liver and kidney function test and normal ACTH stimulation (sensitive) test results. Skin biopsy was done elsewhere, but was not conclusive.

Figure 1

Bluish black discoloration of face, chest, and upper extrimity

Figure 2

Bluish black discoloration of neck and back

Figure 3

Oral mucous membrane and palate are not involved

Discussion

Los cenicientos[3] is a Spanish word that means, “the ashen ones.” It has been a controversial topic that has showed a tendency to appear mostly in dark colored individuals and also in Asians.

Some experts have opined that ashy dermatosis is related to other cutaneous inflammatory diseases. Confusion also arises because the disease is also known by many different names like erythema dyschromicum perstans[45] and lichen planus pigmentosus.[23] Similar kinds of lesions were also observed following the use of ethambutol.[6]

Others have suggested that ashy dermatosis presents clear clinical characteristics but that histopathological findings are not specific.[45]

Our differential diagnoses revolved around lichen planus pigmentosus, occupational dermatosis with hyperpigmentation, drug-related dermatoses, universal acquired melanosis,[7] Allgrove's syndrome,[8] dermatomyositis, and[9] familial progressive hyperpigmentation syndrome. The last one was ruled out by the absence of positive family history. Absence of occupational exposure ruled out occupational dermatosis with hyperpigmentation; dermatomyositis is a condition of muscle weakness, and Allgrove syndrome is characterized by alacrima, achalasia, and ACTH insensitivity. But the patient did not show any of these symptoms and signs. A normal creatinine phosphokinase (CPK) level ruled out the chances of dermatomyositis, and a normal barium meal X-ray and ACTH sensitivity test ruled out Allgrove syndrome. The patient had not taken any drugs in this period.so drug-related dermatosis was ruled out. Universal acquired melanosis is normally seen in infancy. The histopathological study was not conclusive enough to differentiate from Lichen planus pigmentosus but the absence of pruritus, the lack of involvement of the oral mucosa, and the bluish-black discoloration in our patient, a dark colored Indian in his second decade of life support our diagnosis in favor of ashy dermatosis of the idiopathic variety. The only treatment in this condition resulting in considerable improvement in pigmentation is Clofazimine at a dose of 100 mg three times per week for three to five months.[1]