What is postinflammatory hyperpigmentation?
Postinflammatory pigmentation is temporary pigmentation that follows injury (e.g. thermal burn) or inflammatory disorder of the skin (e.g. dermatitis, infection). It is mostly observed in darker skin types. Postinflammatory pigmentation is also called acquired melanosis.
More severe injury results in postinflammatory hypopigmentation, which is usually permanent.
What causes postinflammatory hyperpigmentation?
Postinflammatory hyperpigmentation follows damage to the epidermis and/or dermis with deposition of melanin within the keratinocytes (skin cells) and/or dermis..
Inflammation in the epidermis stimulates melanocytes to increase melanin synthesis and to transfer the pigment to surrounding keratinocytes (epidermal melanosis). If the basal layer is injured (e.g. lichen planus), melanin pigment is released and subsequently trapped by macrophages in the papillary dermis (dermal melanosis or pigment incontinence). Dermal pigment tends to be a grey brown.
Postinflammatory pigmentation tends to become darker and more noticeable with sun exposure, so sun protection and broad-spectrum sunscreens are an important part of management. Although peeling agents may reduce epidermal pigmentation, nothing has been found useful to eradicate dermal melanosis.
What is the treatment for postinflammatory hyperpigmentation?
Topical treatments for postinflammatory hyperpigmentation
A variety of topical treatments are available to lighten/bleach hyperpigmented lesions in epidermal hypermelanosis. Varying degrees of success are achieved but combinations of the treatments below are usually required for significant improvement.
- Azelaic acid
- Vitamin C cream
- Tretinoin cream
- Corticosteroid creams
- Glycolic acid peels
- Others: kojic acid, arbutin, licorice extracts, mequinol, niacinamide, N-acetyl glucosamine, soy
Physical treatments for postinflammatory hyperpigmentation
These treatments are not effective in dermal hypermelanosis.