The terms Erythema Dyschromicum Perstans (EDP), Lichen Planus Pigmentosus (LPP) and Idiopathic Eruptive Macular Pigmentation (IEMP) are names given to pigmentary disorders and often used interchangeably. Even pigmentary disorder experts around the world differ in their opinion about the features of these conditions!
Erythema Dyschromicum Perstans (EDP)
Also known as…Ashy Dermatosis
EDP was first described by Ramirez in El Salvador in the 1950s. The condition is seen most commonly in women and in those with more deeply pigmented skin including Latin Americans and Asians.
EDP usually affects people between the ages of 20 to 30. It tends to involve areas of the body that do not get exposed to the sun.
EDP is chronic and is challenging to treat. While hydroquinone and tretinoin are helpful in some pigmentary conditions such as melasma and post-inflammatory hyperpigmentation, they do not work very well for EDP.
Dapsone and clofazamine have been described as being helpful for some people.
While many other treatments have been evaluated including topical steroids and chloroquine, none have resulted in significant lightening. More research is needed to increase treatment options.
Lichen Planus Pigmentosus (LPP)
LPP is a rare variant of lichen planus usually seen in middle-aged individuals with more deeply pigmented skin (e.g. South Asians, South-East Asians and the Arabic population).
LPP may present with itchy, scaly brown-grey spots without red borders.
The condition most commonly affects sun-exposed sites such as the head (forehead and temples) and neck but spots are often seen in skin folds such as the armpits (LPP inversus) and in some cases the mucosal surfaces (e.g. the mouth). Unlike EDP, LPP does not have any lesions with red borders.
Although the exact cause of LPP is unknown, ultraviolet light has been implicated due to the location of the spots. Mustard and amla oils have been reported as possible causes in some studies.
Sunscreen and sun-protection are very important in the treatment of LPP. Various small studies reveal tacrolimus cream, corticosteroid creams and tablets and vitamin A creams may be helpful in treating LPP.
Further research is needed to increase treatment options.
This information has been written by Dr Michelle Rodrigues