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Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Postinflammatory hyperpigmentation

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.

More severe injury results in postinflammatory hypopigmentation, which is usually permanent.

What are the clinical features of postinflammatory hyperpigmentation?

Postinflammatory hyperpigmented patches are located at the site of the original disease after it has healed. The lesions range from light brown to black in colour. The patches may become darker if exposed to sunlight (UV rays).

Postinflammatory pigmentation
Lichen planus actinicus
Postinflammatory pigmentation. Violin playing (friction)
Violin playing (friction)
Postinflammatory pigmentation. Irritant dermatitis
Irritant dermatitis
Postinflammatory hyperpigmentation  (inflamed cyst)
Postinflammatory hyperpigmentation (inflamed cyst)
Postinflammatory pigmentation. Oven burn
Oven burn
Postinflammatory pigmentation. Photodynamic therapy
Photodynamic therapy
Postinflammatory pigmentation. Flagellate reaction to bleomycin
Flagellate reaction to bleomycin
Postinflammatory pigmentation. Healed eczema
Healed eczema
Postinflammatory pigmentation

Who gets postinflammatory pigmentation?

Postinflammatory hyperpigmentation can occur in anyone, but is more common in darker skinned individuals, in whom the colour tends to be more intense and persist for a longer period than in lighter skin colours. 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).

Some medications may also darken postinflammatory pigmentation. These include antimalarial drugs, clofazimine, tetracycline, anticancer drugs such as bleomycin (flagellate erythema), doxorubicin, 5-fluorouracil and busulfan.

What causes postinflammatory hyperpigmentation?

Postinflammatory hyperpigmentation follows damage to the epidermis and/or dermis.

Postinflammatory hyperpigmentation can be due to increased melanin or melanosis within epidermal cells (the outer layer of the skin) or deposited in the dermis (the deeper layer of the skin).

Epidermal melanosis follows inflammatory responses of the epidermis to disease or trauma, which results in the release and oxidation of arachidonic acid to prostaglandins, leukotrienes, interleukin-1 and other products. Fibroblasts in the dermis produce keratinocyte and melanogenic growth factors. These products alter the activity of immune cells and melanocytes. An increased number of melanocytes produce more melanin (skin pigment), which is transferred to surrounding keratinocytes (skin cells).

Dermal melanosis 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 papillary dermis (the top part of the dermis). The dermal pigment may be trapped by large immune cells called tissue macrophages.

Conditions causing postinflammatory hyperpigmentation include:

How is postinflammatory hyperpigmentation diagnosed?

Postinflammatory 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.

What is the treatment for postinflammatory hyperpigmentation?

Usually, hyperpigmentation will gradually lessen over time and normal skin colour will return. However, this is a long process that may take up to 6–12 months or longer. Patients should be advised to use broad spectrum sunscreens daily to reduce further darkening when outdoors.

Cosmetic camouflage using pigmented makeup can also be used to disguise hyperpigmented skin to a hue that is similar to surrounding unaffected skin.

Topical treatments

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.

Physical treatments

Chemical peels, laser treatments and intense pulsed light therapies (IPL) may be helpful, but may also aggravate pigmentation.

These treatments are not effective in dermal hypermelanosis.

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Author: Vanessa Ngan, staff writer. Updated by A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. September 2014.

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If you have any concerns with your skin or its treatment, see a dermatologist for advice.