C. Oswaldo Ramirez of San Salvador, El Salvador, first described erythema dyschromicum perstans (EDP) in 1957.  He called the patients with this eruption Los cenicientos, meaning the ashen ones. The Spanish term cenicienta also means Cinderella because of this folklore character's close association with ashes from sitting at home alone by the fireplace. Later, erythema dyschromicum perstans was called dermatosis ceniciento, meaning ashy dermatosis, because of its ashy bluish gray color. The term erythema dyschromicum perstans is credited to Marion B. Sulzberger, who suggested it when examining Convit's  patients in Caracas. Sulzberger's comment, in discussion of another paper, is as follows:
... the narrow red border (which is often hard to find), represents the active lesions. This is why I suggested a name which contains the term "erythema" and which also suggests the variety and persistence of the final dyschromias.
The descriptive term ashy dermatosis was also used as a designation for their coloration. In South America, another name, erythema chronicum figuratum melanodermicum, is also used.
The etiology of erythema dyschromicum perstans is unknown, but many consider erythema dyschromicum perstans to be a variant of lichen planus actinicus. A variety of predisposing factors have been cited. These include ingestion of ammonium nitrite, an intestinal parasitosis caused by nematodes (whipworm infection, control of which produced erythema dyschromicum perstans remission), orally administered radiographic contrast media, and, possibly, an occupationally associated cobalt allergy in a plumber. One case may be particularly revealing, that of a 13-year-old rural northern European truant who repeatedly ingested small amounts of a fertilizer, ammonium nitrate, to induce erythema dyschromicum perstans and avoid school. Chlorothalonil exposure among banana farm workers is another possible cause of erythema dyschromicum perstans. 
An abnormality in cell-mediated immunity might play a role. However, substantial immune dysfunction is limited at present to 1 report of an HIV-seropositive 41-year-old homosexual of Chinese lineage with erythema dyschromicum perstans. [7, 8]
HLA-DR association with the genetic susceptibility to develop ashy dermatosis in Mexican Mestizo patients was analyzed, the results of which were reported by Correa in 2007.  The most frequent allele was HLA-DR4 (65%), compared with 23% in controls. These Mexican patients had HLA-DR4 subtype *0407, which is also found in the Amerindian population. [10, 11] Thus, although many factors may be involved, an important genetic susceptibility appears to be conferred by genes located within the major histocompatibility complex region.
Erythema dyschromicum perstans is most common in Latin America and Asia; most of the cases occur in El Salvador where the first case was identified. Cases in Europe have also been described, including in Italy. 
Darker-skinned individuals seem to be affected more often than lighter-skinned individuals. It is a rare disorder of pigmentation that is most common in Hispanic patients.  It may also occur in children from the Indian subcontinent.  Unlike adult patients, who are most commonly of Hispanic origin, children with erythema dyschromicum perstans are usually white. [15, 16]
Both sexes are affected, but women are affected more often than men.
The age range affected is wide, both in Latin America and around the world. Erythema dyschromicum perstans has been observed in children aged 1 year and adults aged 80 years. For example, a 6-year-old British girl and 4 Finnish children aged 8-12 years were described, as were many older patients. An early report had a series of 5 patients; 3 males aged 11-36 years and 2 women.
Erythema dyschromicum perstans may persist for years. Erythema dyschromicum perstans has a benign outcome, with most complaints relating to cosmetic issues.