The visual impact of changes in pigmentation depends on the racial skin type. Vitiligo is more noticeable in people with dark skin and this is complicated by the cultural context: confusion with leprosy gives an extra stigma in some cultures, making it difficult for a woman with vitiligo to marry. Post-inflammatory hyper-pigmentation is more obvious in darker skin, making it more important to treat inflammatory conditions such as acne effectively.

Effect of Inflammation

Skin inflammation can cause increased (hyper) or decreased (hypo) pigmentation. Psoriasis plaques may leave pale areas after recovery that persist for years. Post-inflammatory hyperpigmentation can be severe if there is deep epidermal disruption (e.g. lichen planus). It follows the pattern of inflammation, which may be diagnostic (e.g. after herpes zoster). Pigmentation may follow trauma (Figure 37.2). Facial acne lesions can leave areas of increased pigmentation.

Skin Lighteners

Lightening of Skin Colour

Reasons for desiring cosmetic skin lightening include cultural attitudes, a view that whiter skin is more attractive, and powerful influences from advertising by cosmetic companies. Medical indications for skin lightening include localised post-inflammatory pigmentation, treatment of solar lentigines and very widespread vitiligo if the normal darker skin appears abnormal. Reasons not to lighten skin colour include: natural skin colour is normal and attempts at lightening may not produce cosmetic benefit and may result in unnatural pigment variation.

How to Lighten Skin

Topical hydroquinone can be used alone, but it can be irritant and can cause irregular depigmentation. Hydroquinone is banned from cosmetics in Europe. Hydroquinone may be combined with topical tretinoin and/or topical steroids. Azaleic acid may be used. This chemical is produced by Malassezia furfur and causes the pigmentary changes in pityriasis versicolor.