Patchy skin color is areas where the skin color is irregular. Mottling or mottled skin refers to blood vessel changes in the skin that cause a patchy appearance.
Irregular or patchy discoloration of the skin can be caused by:
Changes in melanin, a substance produced in the skin cells that gives skin its color
Growth of bacteria or other organisms on the skin
Blood vessel (vascular) changes
The following can increase or decrease melanin production:
Exposure to radiation (such as from the sun)
Exposure to heavy metals
Changes in hormone levels
Exposure to sun or ultraviolet (UV) light, especially after taking a medicine called psoralens, may increase skin color (pigmentation). Increased pigment production is called hyperpigmentation.
Decreased pigment production is called hypopigmentation.
Skin color changes can be their own condition, or they may be caused by other medical conditions or disorders.
How much skin pigmentation you have can help determine which skin diseases you may be more likely to develop. For example, lighter-skinned people are more sensitive to sun exposure and damage, which raises the risk of skin cancers. But even in darker-skinned people, too much sun exposure can lead to skin cancers.
Generally, skin color changes are cosmetic and do not affect physical health. However, mental stress can occur because of pigment changes. Some pigment changes may be a sign that you are at risk of other medical disorders.
Causes of pigment changes may include any of the following:
In some cases, normal skin color may return on its own.
You may use lotions that bleach or lighten the skin to reduce discoloration or to even the skin tone where hypopigmented areas are large or very noticeable. Follow the instructions on the package about how to use such products.
Selenium sulfide (Selsun Blue), ketoconazole, or tolnaftate (Tinactin) lotion can help treat tinea versicolor. Apply as directed to the affected area daily until the discolored patches disappear. Tinea versicolor often returns, even with treatment.
You may use cosmetics or skin dyes to hide skin color changes. Makeup can also help hide mottled skin, but it will not cure the problem.
Avoid too much sun exposure and use sunblock with an SPF of at least 30. Hypopigmented skin sunburns easily, and hyperpigmented skin may get even darker. In darker-skinned people, skin damage may cause permanent hyperpigmentation.
When to Contact a Medical Professional
Contact your doctor if:
You have any lasting skin color changes that do not have a known cause
An existing growth has changed color, size, or appearance
What to Expect at Your Office Visit
The doctor will carefully examine your skin and ask about your medical history. You will also be asked about your skin symptoms, such as when you first noticed your skin color change, it if started suddenly, and if you had any skin injuries.
Yohn J. Disorders of pigmentation. In: Fitzpatrick JE, Morelli JG, eds. Dermatology Secrets Plus. 4th ed. Philadelphia, PA: Elsevier Mosby; 2010:chap 18.
Richard J. Moskowitz, MD, Dermatologist in private practice, Mineola, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.