Skin Pigmentation Disorders

How skin color works

Melanocytes in the bottom layer of the epidermis make melanin and pass it to surrounding skin cells. Everyone has roughly the same number of melanocytes; skin tone depends on how much and what type of melanin they make. Sunlight, hormones, inflammation and genetics all affect production.

Pigmentation disorders fall into three groups:

• Hyperpigmentation: excess melanin, causing brown, gray-brown or blue-gray patches
• Hypopigmentation: reduced melanin, causing lighter patches
• Depigmentation: complete loss of melanin, causing chalk-white patches

Pigment changes are often more visible and longer-lasting in medium and darker skin tones.

Types of hyperpigmentation (darker patches)

For a symptom-focused guide to dark patches, see hyperpigmentation.

Types of hypopigmentation and depigmentation (lighter patches)

Other color changes

Not all discoloration comes from melanin. Yellow skin may be jaundice from liver disease or carotenemia from eating many carrots. Blue-gray skin can come from low oxygen or silver deposits. Red or purple patches usually reflect blood vessels or bruising. Our guide to skin discoloration covers these.

Causes and risk factors

• Sun exposure: the biggest trigger of hyperpigmentation and worsens almost all pigment disorders
• Hormones: pregnancy, oral contraceptives and hormone therapy (melasma)
• Skin inflammation or injury: acne, eczema, bug bites, cuts, harsh treatments
• Genetics: albinism, freckling, tendency to melasma and vitiligo
• Autoimmune disease: vitiligo is linked with thyroid disease and type 1 diabetes
• Medicines and chemicals
• Endocrine and metabolic diseases: Addison's disease, hemochromatosis, insulin resistance

How pigmentation disorders are diagnosed

A dermatologist usually diagnoses them by appearance and history. Tests may include:

• Wood's lamp: an ultraviolet light that makes vitiligo glow bright white and shows how deep melasma pigment sits
• Dermatoscopy: magnified examination to check moles and spots for features of melanoma
• Skin scraping: for yeast in tinea versicolor
• Skin biopsy: for uncertain or changing lesions
• Blood tests: thyroid function with vitiligo, cortisol testing if Addison's is suspected, glucose or HbA1c with acanthosis nigricans, iron studies for hemochromatosis

Treatment

For dark patches

• Strict sun protection: broad-spectrum SPF 30 or higher daily, reapplied every 2 hours outdoors. Tinted sunscreens with iron oxides also block visible light, which helps melasma
• Lightening agents: hydroquinone (short courses), azelaic acid, kojic acid, vitamin C, niacinamide, tranexamic acid
• Retinoids: tretinoin or adapalene speed cell turnover
• Triple-combination cream (hydroquinone, a retinoid and a mild steroid) for melasma
• Chemical peels and lasers: effective for sun spots; used cautiously in darker skin and melasma because they can worsen pigmentation
• Treat the cause: clear acne early, manage insulin resistance, change a causative drug

Avoid unregulated "skin whitening" products, which may contain mercury or high-strength steroids.

For light patches

• Vitiligo: topical steroids, calcineurin inhibitors (tacrolimus, pimecrolimus), ruxolitinib cream (an FDA-approved JAK inhibitor for vitiligo), narrowband UVB light therapy, and in stable cases surgical grafting
• Tinea versicolor: antifungal shampoos, creams or tablets; color takes months to even out after the yeast is cleared
• Post-inflammatory hypopigmentation: treat the underlying skin condition; color usually returns slowly
• Cosmetic camouflage with makeup or self-tanner

Outlook

Many pigment changes, especially post-inflammatory marks, fade over 6 to 12 months or longer. Melasma and vitiligo are chronic and can relapse, but treatment usually improves them. Albinism is lifelong and needs careful sun and eye protection.

Frequently asked questions

What are the most common skin pigmentation disorders?

The most common are sun spots (solar lentigines), freckles, melasma and post-inflammatory hyperpigmentation, which cause darker patches, and vitiligo, tinea versicolor and post-inflammatory hypopigmentation, which cause lighter patches. Albinism is rarer and inherited.

What causes skin pigmentation problems?

Sun exposure is the main trigger. Others include hormones, skin inflammation or injury, genetics, autoimmune disease, certain medicines, fungal infection and, less often, hormonal or metabolic illnesses such as Addison's disease, hemochromatosis or insulin resistance.

Can skin pigmentation be permanently removed?

Some can be removed with lasers or peels, such as sun spots. Others, like melasma, often return with sun exposure or hormonal changes, so ongoing sun protection and maintenance treatment are needed. Post-inflammatory marks usually fade by themselves over months.

When is a dark spot on the skin a concern?

See a doctor if a spot is new in adulthood, has an irregular border or several colors, is larger than a pencil eraser, or is changing, itching or bleeding. These are warning signs of melanoma. A dark streak under a nail without injury also needs checking.

Is vitiligo a pigmentation disorder?

Yes. Vitiligo is an autoimmune pigmentation disorder in which the immune system destroys melanocytes, leaving sharply defined white patches. It is not contagious or harmful to general health, though it is linked with thyroid disease. Treatments can restore color in many people.