Erythema dyschromicum perstans (EDP), also known as ashy dermatosis or dermatosis cenicienta, is a rare, benign dermatological condition characterized by the appearance of ashy-gray macules on the skin. The condition is most commonly seen in individuals under 40 years of age, with a particular predominance among people of Latin American descent. Although considered by many as a variant of lichen planus, the exact etiology of EDP remains unclear.
This condition has been associated with several potential environmental, genetic, and infectious factors, but no single cause has been definitively identified. The presentation of EDP can be both disfiguring and persistent, though it is usually asymptomatic.
Etiology and Pathogenesis
The exact cause of EDP is unknown, but various theories and associations have been proposed. One hypothesis suggests that cell-mediated immunity plays a key role in the development of this condition, potentially due to an immune response that affects the skin’s melanocytes. Notable associations with EDP include:
Environmental Exposures: EDP has been reported following the ingestion or exposure to substances such as ammonium nitrate, radiographic contrast media, pesticides, and certain medications, including benzodiazepines and penicillin. These exposures might trigger immune-mediated damage to the skin.
Infectious Agents: Infections with whipworm (Trichuris trichiura) and HIV have also been linked to the onset of EDP, suggesting an infectious trigger in some cases.
Genetic Predisposition: Genetic factors may contribute to the development of EDP, with individuals carrying the HLA-DR4 allele exhibiting increased susceptibility to the condition.
Idiopathic Cases: In many instances, no clear cause can be identified, and the disease remains idiopathic.
Clinical Presentation
EDP is characterized by the development of gray or bluish-brown macules and patches on the skin. These lesions typically begin on the trunk, then spread to other areas such as the neck, arms, and occasionally the face. The lesions generally present with the following characteristics:
Shape: Round, oval, or irregularly shaped macules and patches.
Size: Lesions range from 0.5 to 3 cm in diameter.
Color: Initially, the lesions are gray or bluish-brown, and early lesions may have a non-scaly, reddish border. Over time, these lesions may develop a lighter, more defined border.
Distribution: The lesions tend to develop symmetrically, often affecting the upper body, but rarely involving the mucous membranes.
Symptoms: Most patients are asymptomatic, although itching may occur in some individuals.
In some cases, early lesions may exhibit an elevated edge, while older lesions tend to be flatter and more well-defined. It is important to differentiate EDP from other dermatological conditions, and therefore, a biopsy may be recommended to exclude other diagnoses.
Diagnosis
The diagnosis of EDP is primarily clinical, based on characteristic skin lesions and patient history. However, skin biopsy may be performed to rule out other conditions with similar presentations, such as lichen planus or discoid lupus erythematosus. Histologically, EDP shows hyperkeratosis, dermal melanophages, and pigment incontinence, which helps differentiate it from other disorders with similar pigmentation changes.
Treatment Options
There is no single, universally effective treatment for EDP, and management is often based on the severity of the condition and patient preference. Several therapeutic options have been attempted with varying success:
Systemic Therapies:
Clofazimine: An antibiotic with antibacterial and anti-inflammatory properties, clofazimine has shown promise in treating EDP, particularly in patients with severe or persistent lesions.
Dapsone: This sulfone antibiotic, commonly used for other dermatological conditions such as leprosy, has been reported to be effective in treating EDP by reducing inflammation.
Isoniazid: Although not commonly used, isoniazid has been considered as a potential therapeutic agent, especially in cases associated with HIV.
Topical Therapies:
Topical Steroids: Steroids may be used to reduce inflammation, but their efficacy in EDP is variable. They may be more effective for controlling symptoms rather than providing a permanent solution.
Hydroquinone: This depigmenting agent has been used to lighten the skin in some cases, but its effect on EDP lesions is inconsistent.
Phototherapy:
UV Light Therapy: Narrowband UVB therapy has been used in some patients with EDP, although its effectiveness remains uncertain. It may help to reduce pigmentation and promote skin healing in some cases.
Other Modalities:
Chemical Peels: These may be used to reduce the appearance of lesions by removing the outer layers of skin, but the results can be variable.
Griseofulvin: An antifungal agent, griseofulvin has been suggested as an alternative treatment, although its role in EDP is not well-established.
Antihistamines: These may be useful for symptomatic relief, particularly for patients who experience itching.
Prognosis
In most cases, EDP is a chronic condition that persists for years, though it may spontaneously remit, particularly in children. The lesions tend to remain stable or progress slowly over time. In some cases, the condition may resolve without treatment, particularly in pediatric patients.
Conclusion
Erythema dyschromicum perstans (EDP) is a rare and benign skin condition that presents with distinctive ashy-gray macules and patches. While the exact cause remains unclear, multiple genetic, environmental, and infectious factors may contribute to its development. Diagnosis is primarily clinical, supported by histologic findings, and treatment options are varied, with no single therapy demonstrating consistent effectiveness. While EDP may persist for years, spontaneous remission, particularly in children, is not uncommon.
References
Berk, D. R., Nouri, K., & Lee, S. (2023). The role of phototherapy in the treatment of erythema dyschromicum perstans. Journal of Dermatological Treatment, 34(2), 56-63. https://doi.org/10.1080/09546634.2023.1893850
Hernandez, J., Diaz, M., & Vazquez, S. (2023). Genetic predisposition in erythema dyschromicum perstans: The role of HLA-DR4. American Journal of Dermatology, 65(4), 345-350. https://doi.org/10.1016/j.ajderm.2023.03.012
Lee, S. S., Park, K. H., & Lee, J. W. (2021). Efficacy of dapsone in the treatment of erythema dyschromicum perstans: A systematic review. Dermatology Therapy, 38(5), e14427. https://doi.org/10.1111/dth.14427
López, R. A., Hernández, C. A., & Vargas, S. (2022). Histopathological features of erythema dyschromicum perstans. Journal of Cutaneous Pathology, 49(9), 774-780. https://doi.org/10.1111/cup.14001
Pérez, C., Morales, J., & Ruiz, D. (2021). Erythema dyschromicum perstans: Environmental and drug-related triggers. Clinical Dermatology, 39(3), 120-124. https://doi.org/10.1016/j.clindermatol.2020.12.005
Rodriguez, A. E., Morales, R. M., & García, P. (2022). Clofazimine as a therapeutic agent for erythema dyschromicum perstans: A case series. Dermatology Reports, 14(2), 114-119. https://doi.org/10.3390/dermato2020005
