Hypopigmented scars

Hypopigmented scars are not caused by structural or functional defects of primary melanocytes, but are secondary hypopigmented diseases at the site of acquired inflammation.

I. Etiology and pathogenesis

This disease is often caused by the following factors:
(1) It is often seen after a variety of inflammatory skin diseases.
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(2) Scars after burns or ulcers. (3) Hypopigmentation after skin freezing, laser, radionuclide and other treatments. (4) Hypopigmentation after certain skin diseases: such as lupus erythematosus, lichen planus, lichen sclerosus atrophicus, psoriasis and neurodermatitis.
The pathogenesis of this disease may be related to the following factors: melanocyte deficiency, abnormal melanocyte transport, inhibition of melanin biosynthesis by chemicals, and impaired protection mechanisms against ultraviolet rays.

II. Clinical manifestations

Hypopigmentation occurs at the site of inflammatory damage, and the boundaries are often unclear; the degree of hypopigmentation is often not as obvious as vitiligo, and atrophic scars of varying degrees can be seen on some hypopigmented skin lesions.

III. Pathological characteristics

In addition to the tissue image after the primary inflammatory disease, the disease has a decrease in melanocytes and a lack of melanin granules in the skin.

IV. Diagnosis and differential diagnosis

This disease is not difficult to diagnose based on the history of inflammation and hypopigmented spots. This disease is mainly differentiated from vitiligo. Vitiligo often occurs suddenly, and the rash can be seen in any part of the body, especially in exposed and frictional parts. The oral cavity, glans mucosa and other parts may also be involved. The skin lesions are depigmented spots of varying sizes with clear boundaries. There is no inflammatory damage to the local skin before the lesions occur. There is no scale on the surface of the lesions, and no atrophic scars exist.

V. Treatment

The treatment of this disease is mainly to treat the primary disease. For those with hypopigmented spots in the damaged area that have not healed for a long time, surgical excision, skin grafting, flap transfer and other methods can be used. For hypopigmented spots that are unwilling to undergo surgical treatment or are limited and not suitable for surgical treatment, CO, laser-assisted autologous epidermal transplantation can be used. The specific method is the same as the treatment of vitiligo, but the scar tissue has poor blood supply, which affects the survival of the skin graft. According to statistics, the survival rate of the skin graft is only 67.5%. After skin grafting, local bandaging and fixation are very important, otherwise it will affect the survival of the skin graft. Its main complications include pigmentation deepening, local unevenness, etc. There are also clinical reports that the use of 1550nm erbium fractional laser combined with bimatoprost and retinoic acid or pimecrolimus topical treatment of hypopigmented scars has a certain improvement effect without obvious adverse reactions.

Source: Hypopigmented scars