Skin Discoloration: Causes by Color

Why skin color changes

Skin color comes mainly from melanin, made by pigment cells called melanocytes, along with blood flow and substances such as bilirubin and carotene. Discoloration happens when:

• melanocytes make too much melanin (darker patches) or too little (lighter patches)
• blood flow or oxygen levels change (red, pale, blue or purple skin)
• a substance builds up in the skin (yellow, bronze or gray tones)

Changes in pigment are often more visible and longer-lasting in darker skin tones.

Dark patches (hyperpigmentation)

Light patches (hypopigmentation)

• Vitiligo: milk-white, well-defined patches from loss of pigment cells, often around the eyes, mouth, hands and genitals. It is autoimmune and sometimes linked to thyroid disease.
• Tinea versicolor: small, slightly scaly pale, pink or tan patches on the chest, back and shoulders, caused by a yeast. More noticeable after tanning.
• Pityriasis alba: faint, pale, slightly scaly patches on the faces of children with dry skin or eczema.
• Post-inflammatory hypopigmentation: pale marks after eczema, psoriasis, burns or skin treatments.
• Idiopathic guttate hypomelanosis: small white spots on sun-exposed shins and arms in older adults.
• Rarely, leprosy (numb pale patches) and some skin lymphomas.

Red, yellow, blue and other color changes

• Red: blushing, rosacea, eczema, sunburn, infection, allergic reactions. See skin redness.
• Yellow: jaundice from liver disease, gallstones or red cell breakdown, with yellow whites of the eyes. Eating lots of carrots causes yellow-orange palms (carotenemia) but leaves the eyes white.
• Pale: anemia, shock, low blood pressure, poor circulation.
• Blue or gray (cyanosis): low oxygen from lung or heart problems, or cold exposure. Blue fingers in the cold that turn white then red suggest Raynaud's phenomenon.
• Purple or red spots that do not blanch: bleeding under the skin (petechiae, purpura, bruising).
• Brown, discolored lower legs: long-standing venous insufficiency.

When skin discoloration could be melanoma

Use the ABCDE check for dark spots and moles:

• Asymmetry: one half does not match the other
• Border: ragged, notched or blurred edges
• Color: several shades, or black, blue, red or white areas
• Diameter: larger than 6 mm (a pencil eraser), though melanomas can be smaller
• Evolving: changing in size, shape, color or symptoms such as itching or bleeding

Also watch for the "ugly duckling", a spot that looks different from your other moles. A dark streak in a nail or a new dark patch on the palm or sole also needs checking.

How doctors diagnose skin discoloration

A doctor or dermatologist examines the skin, often with a dermatoscope, and may use a Wood's lamp (ultraviolet light) that makes vitiligo glow bright white and tinea versicolor fluoresce. Scrapings test for fungus, and a biopsy checks suspicious spots. Blood tests are used when a body-wide cause is suspected: liver function for jaundice, blood count for anemia, blood sugar for acanthosis nigricans, thyroid tests in vitiligo, and cortisol tests for Addison's disease.

Skin discoloration treatment

Dark patches

• Daily broad-spectrum sunscreen of SPF 30 or higher, reapplied every 2 hours outdoors. Tinted sunscreens with iron oxides help melasma. Without sun protection, other treatments do not last.
• Topical lighteners: hydroquinone, azelaic acid, kojic acid, vitamin C, niacinamide and retinoids. Prescription combination creams for melasma.
• Procedures: chemical peels, laser and cryotherapy for sun spots, used cautiously in darker skin, which can darken further after treatment.
• Treat the cause: control acne and eczema, improve insulin resistance with weight loss and exercise, review medicines.

Light patches

• Vitiligo: steroid or calcineurin inhibitor creams, ruxolitinib cream, narrowband UVB light therapy, and camouflage makeup. Early treatment works best.
• Tinea versicolor: antifungal shampoos (selenium sulfide or ketoconazole) applied to the skin, or antifungal tablets. Color takes months to even out after the yeast is cleared.
• Pityriasis alba and post-inflammatory changes: moisturizers, sun protection and time.

Frequently asked questions

What causes skin discoloration?

The most common causes are sun damage, melasma, marks left after acne or eczema, fungal infections such as tinea versicolor, and vitiligo. Discoloration can also signal internal problems such as jaundice from liver disease, insulin resistance, low oxygen or hormonal conditions.

What causes dark patches on the skin?

Sun spots, melasma (often hormonal), post-inflammatory marks after acne or eczema, acanthosis nigricans linked to insulin resistance, and some medicines. A dark spot that is changing or irregular should be checked for melanoma.

What causes white patches on the skin?

Vitiligo, tinea versicolor, pityriasis alba in children, and pale marks after inflammation are the commonest causes. Vitiligo patches are milk-white and sharply defined. Tinea versicolor patches are slightly scaly and often on the chest and back.

Can skin discoloration be reversed?

Many types fade with treatment and strict sun protection, although it often takes months. Post-inflammatory marks fade over 6 to 12 months or more. Melasma can be controlled but often returns with sun or hormones. Vitiligo can repigment with treatment, especially on the face.

When should I worry about skin discoloration?

See a doctor for a changing or irregular dark spot, yellow skin or eyes, blue or gray lips, widespread darkening with tiredness and weight loss, or patches that are spreading or not improving after 3 months.