What is the Difference Between Dermal and Epidermal Melasma?

Melasma is a skin condition characterized by dark patches appearing on the face, primarily on the forehead, cheeks, and upper lip. It is caused by excessive pigment (melanin) collecting in the skin. Melasma can be categorized as "epidermal" or "dermal," or mixed. The key differences between dermal and epidermal melasma are:

• Epidermal Melasma: This type of melasma affects the more superficial layers of the skin called the epidermis. Epidermal melasma is characterized by well-defined brown patches. It is often associated with hormonal changes, such as pregnancy or birth control use. Epidermal melasma generally responds more quickly to treatment.
• Dermal Melasma: This type of melasma penetrates deeper into the skin, affecting the dermal layer. Dermal melasma is characterized by less defined brown or gray patches. It may be more common in individuals with a family history of the condition. Dermal melasma is generally more challenging to treat compared to epidermal melasma.

Treatment options for both dermal and epidermal melasma may include bleaching agents, topical creams or gels, chemical peeling, and laser therapy. The choice of treatment depends on the type of melasma and individual factors. It is essential to identify the specific type of melasma for effective treatment. A doctor may use a Wood's Lamp to determine the type of melasma.

Comparative Table: Dermal vs Epidermal Melasma

Melasma is a hyperpigmentary condition that can be classified into three types based on the depth of melanin deposition: epidermal, dermal, and mixed. Here is a table summarizing the differences between dermal and epidermal melasma:

Epidermal melasma is characterized by melanin deposition in the epidermal layer, which can be seen with a Wood's lamp as accentuation under light. Dermal melasma, on the other hand, has melanin deposited in the dermal layer, showing no accentuation under a Wood's lamp. Dermoscopic evaluation reveals different patterns for each type, with epidermal melasma displaying a scattered islands of brown reticular network with fine dark granules on the surface, while dermal melasma shows a brown-to-ash grey color with a more uniform appearance.