Hyperpigmentation, Post-Inflammatory
Hyperpigmentation, Post-Inflammatory Causes
One of the causes of post-inflammatory hyperpigmentation is the release and oxidation of arachidonic acid to leukotrienes, prostaglandins and other products is due to the inflammatory responses of the epidermal skin layer to disease or trauma, where they may alter the activity of immune cells and melanocytes. Known as epidermal hypermelanosis, melanocytes produce more melanin (skin colour pigment), which is transferred to surrounding keratinocytes (skin cells). Dermal hypermelanosis is also another cause, which is a deeper pigmentation that occurs when inflammation disrupts the basal cell layer (the bottom of the epidermis), causing melanin pigment to be released into the paipillary dermis (the top part of the dermis), and the pigment may be trapped by large immune cells called tissue macrophages.
Hyperpigmentation, Post-Inflammatory Definition
The darkening of the skin in an area of prior injury or skin disorder from increased pigment (melanin) left from the healing process is called post-inflammatory hyperpigmentation. When old red blood cells die, the darkening may sometimes be also due to an iron pigment left behind.
Hyperpigmentation, Post-Inflammatory Symptoms and Signs
Among the signs and symptoms of post-inflammatory hyperpigmentation is one or more areas of darker brown or sometimes red-brown discoloration. Its appearance may vary in shape, size and location depending upon the cause of the skin injury. Insect bites, burns, cuts, or scrapes often affect exposed areas on the legs and arms while acne tends to leave light to dark brown spots on the trunk or face.
Hyperpigmentation, Post-Inflammatory Treatment
2-4% of hydroquinone, tazarotene, hydroquinone, azelaic acid and glycolic acid are some products or some creams that may help fade dark marks and are often used in combination. Not generally covered by insurance, chemical peels or microdermabrasion are treatments that need to be repeated monthly for a total of 4-6 sessions, and they may cause further darkening and irritation if not done by experts.