Post Inflammatory 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. Post Inflammatory Pigmentation is also called acquired melanosis.
More severe injury results in Post Inflammatory Hypopigmentation, which is usually permanent.
Who Gets Post Inflammatory Pigmentation?
Post Inflammatory Hyperpigmentation can occur in anyone, but is more common in darker skinned individuals, in whom the color tends to be more intense and persist for a longer period than in lighter skin colors. Pigmentation tends to more pronounced in sun-induced skin conditions such as phytophotodermatitis and lichenoid dermatoses (skin conditions related to lichen planus, such as erythema dyschromicum perstans).
What Causes Post Inflammatory Pigmentation?
Post Inflammatory 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.
Post Inflammatory Hyperpigmentation 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 are the Clinical Features of Post Inflammatory Hyperpigmentation?
Post Inflammatory Hyperpigmented patches are located at the site of the original disease after it has healed. The lesions range from light brown to black in color. The patches may become darker if exposed to sunlight (UV rays).
How Is Post Inflammatory Hyperpigmentation Diagnosed?
Post Inflammatory Hyperpigmentation is diagnosed by taking a careful history and examining the skin. Dermal melanosis gives a characteristic hue to the skin colour (grey-purple-brown).
Sometimes the diagnosis is only made after skin biopsy. Histopathology reveals patchy epidermal melanosis and/or dermal melanosis.
Treatment for Inflammatory Pigmentation?
Some medications may also darken post inflammatory pigmentation. These include antimalarial drugs, clofazimine, tetracycline, anticancer drugs such as bleomycin (flagellate erythema), doxorubicin, 5-fluorouracil and busulfan.
If pigmentation affects an exposed site, daily application of SPF 50+ broad-spectrum sunscreen is important to minimize darkening caused by UVR. Cosmetic camouflage can be used.
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 Post Inflammatory Hyperpigmentation
Chemical peels, laser treatments and intense pulsed light therapies (IPL) may be helpful for epidermal pigmentation, but physical treatments may also aggravate it by injuring the epidermis.
Dr. Larry Jaeger is a well known and respected board certified dermatologist and dermatological surgeon who is the medical director of Advanced Dermatology Associates of New York. Dr Larry Jaeger specializes in all aspect of medical, cosmetic and surgical dermatology.