What Is Postinflammatory Hyperpigmentation?

Post-inflammatory pigmentation refers to skin pigmentation that occurs after an acute or chronic inflammatory process on the skin. The degree and duration of skin pigmentation vary from person to person. Dark-skinned people and those who are prone to tanning have more severe pigmentation and last longer, but there is no significant relationship between the severity of skin pigmentation and the severity of inflammation.

Basic Information

Visiting department

dermatology

Common causes

Inflammatory response reduces or partially removes sulfhydryl groups in the skin, reduces sulfhydryl groups, and increases tyrosinase activity

Common symptoms

Clearly demarcated light brown, purple brown to dark black pigmented skin after acute or chronic inflammatory processes

Causes of Pigmentation After Inflammation

Many inflammatory skin diseases can cause pigmentation after skin inflammation. These diseases include lichen planus, lupus erythematosus, fixed drug eruption, shingles, pityriasis rosea, herpes-like dermatitis, subkeratosis, worm dermatitis, Syphilis, mastocytosis, pyoderma, fatty melanocytes, fire-induced erythema, etc. The specific pathogenesis may be due to the reduction or partial removal of sulfhydryl groups in the skin due to the inflammatory response, which reduces the sulfhydryl groups, which increases the tyrosinase activity and causes skin pigmentation. The degree of pigmentation and inflammation is not large, but depends on the characteristics of the skin disease. Post-inflammation pigmentation is also secondary to various physical stimuli (trauma, heat, radiation) and chemical stimuli (drugs, primary stimuli, photosensitizers, allergic infections).

Clinical manifestations of pigmentation after inflammation

1. Pigmentation spots range from light brown, purple brown to dark black. The boundaries are clear and confined to the skin inflammation area. When the erythema subsides, it usually takes weeks to months to gradually resolve. After sun exposure or re-inflammation, the pigment further deepens, even mildly mossy. Some cases persist for several years, and in dark-skinned races, it fades more slowly. Generally not subjective.
2. The cause of pigmentation after inflammation is usually clear, but some initial rashes have not been detected by the patient, or the rash is transient, or it is not easily identifiable clinically. The form and distribution of hyperpigmentation helps to trace the underlying skin diseases, such as lichen planus, fixed drug eruption, shingles, herpes-like dermatitis, and pimples urticaria. Reticulous pigmentation distributed by blood vessels is a characteristic of fire-induced erythema, and it occurs in the skin that is close to the source of fire or in contact with the hot water bottle for a long time.

Post-inflammatory pigmentation examination

Pathological changes: Melanin is deposited in the upper dermis and around the superficial dermis blood vessels, mainly in melanocytes.

Diagnosis of pigmentation after inflammation

1. Previous history of inflammatory skin disease or skin inflammatory irritation.
2. Light brown, purple brown to dark black pigmented spots confined to the skin inflammation area.

Differential diagnosis of pigmentation after inflammation

It needs to be distinguished from Riehl melanosis, tar melanosis, etc. In these facial melanosis, there is no significant capillary expansion and atrophy, but there is often a history of tar or tar product contact.

Pigmentation Treatment After Inflammation

1. Avoid the sun and other inflammatory stimuli as much as possible.
2. Identify the primary inflammatory skin disease, and carry out corresponding preventive treatment to avoid further development of inflammation.
3. Topical application of hydroquinone cream or vitamin A acid cream to promote hypopigmentation.
4. Oral or injection of vitamin C and vitamin E, long-term use can help hypopigmentation.