Definition:

It is a type of acquired macular hyperpigmentation that occurs on the face, neck, and trunk. It is characterized by distinct circular or irregular patches that have a gray color. Erythema dyschromicum perstans is also known as ashy dermatosis (of Ramirez) due to its color.

Epidemiology:

The disease typically manifests in the second or third decade of life, with no predilection for a particular gender. Lesions, however, can develop in old people or very young children.

Etiology:

The precise etiology of erythema dyschromicum perstans remains unknown. Due to its histological characteristics, it is frequently categorized as a form of lichen planus pigmentosus. There are some theories including:

-Genetic predisposition

-Allergic reaction to cosmetics and hair dye

-Viral infections

-An adverse effect of drugs and medications

Clinical features:

-The pigmented patches might be either symmetrical or unilateral in their distribution.

-Early lesions may have an elevated appearance, a more distinct border, and a reddish color. This stage is not necessarily noticeable.

-Other than that, the patient is well and has no related illnesses or abnormal blood tests.

Diagnosis:

Occasionally, the clinical presentation of erythema dyschromicum perstans may exhibit sufficient characteristic features to provide a diagnosis of the condition. A skin biopsy can show mild vacuolar degeneration of the basal layer in initial lesions, and pigmentary incontinence with dermal melanophages in more developed patches.

Management:

Erythema dyschromicum perstans shows a high level of resistance to the treatments currently available. Although it may remain unchanged for years, some cases ultimately resolve on their own.

Possible interventions to enhance appearance of erythema dyschromicum perstans include the following:

-Topical corticosteroids

-Ultraviolet radiation exposure

-Pigment lasers, such as the Q-switched ruby laser

-Chemical peels

Clofazimine has proven to be the most effective systemic therapy. Dapsone, griseofulvin, hydroxychloroquine, isoniazid, and corticosteroids have demonstrated efficacy in a few cases.

Written by:

Mashael Alanazi, medical student.

Resources:

DernNet.
Bolognia Textbook of Dermatology.

Image resource: Bolognia Textbook of Dermatology.