Irregular or patchy discoloration of the skin can be caused by variations in pigment (melanin) density, blood vessel (vascular) changes, or growth of foreign organisms on the skin. Mottling or mottled skin refers specifically to vascular changes in the skin which cause a patchy appearance.
Melanin is a pigment produced in the skin cells that causes skin coloration. An amino acid, tyrosine, is converted to melanin through a series of complex chemical steps in the skin cells. This process may be affected by heredity, heat, trauma, solar or ionizing radiation, heavy metals, and other factors. Pigment production and distribution in the body is regulated in part by hormones.
Changes in any of these factors can result in hyperpigmentation (increase in pigment production), hypopigmentation (decrease in pigment production), or both. The changes may be temporary or permanent. Pigment changes can be primary (existing as a separate disorder) or secondary to (resulting from) other disorders.
A person’s degree of skin pigmentation determines, to some extent, the various dermatological diseases to which a person may be susceptible. Lighter-skinned people are more sensitive to sun exposure and damage and the subsequent development of skin cancer (basal cell carcinoma, squamous cell carcinoma and malignant melanoma). Excessive sun exposure is a risk factor even for darker-skinned people.
Generally, pigment changes are cosmetic and do not affect physical health. However, psychological stress can occur because of pigment changes. Some pigment changes may indicate a risk for other disorders.
- sunburn or sun tan
- uneven application of sunscreen resulting in areas of burn, tan, and no tan
- cuts, scrapes, wounds, insect bites and minor skin infections o skin discoloration during the healing process o with time, the skin coloring generally returns o In darker-skinned people skin damage may cause permanent hyperpigmentation
- moles (nevi) and bathing trunk nevi or giant nevi
- malignant melanoma
- cafe-au-lait spots
- Mongolian blue spots
- pityriasis alba (small circular pale spots on a child’s face, usually the cheeks, often noticeable in the summertime when the skin is tanned)
- tinea versicolor
- mask of pregnancy (also called chloasma or melasma, a dark brown discoloration of the cheeks and the forehead of pregnant women or those using oral contraceptives)
- photosensitivity as a reaction to medications or certain drugs
- radiation therapy
Spontaneous return of normal skin color may occur in some cases. Patience is the most effective measure for loss of skin color.
Exposure to sun or ultraviolet (UV) light, especially after sensitization with an oral medication (psoralens), may increase pigmentation. This may have side effects and may increase the risk for skin cancer.
Lotions that bleach or lighten the skin, such as hydroquinone, may be used to reduce hyperpigmented skin or to even the skin tone where hypopigmented areas are large or conspicuous.
Selsun blue or Tolnaftate (Tinactin) lotion can help in treating tinea versicolor. Apply as directed to the affected area daily until the lesions disappear. Unfortunately, tinea versicolor often returns no matter what type of treatment is used.
Cosmetics or skin dyes may be used to disguise pigmentary changes. Make-up can help hide mottled skin but will not cure the underlying problem.
Avoid excessive sun exposure and use sun block because hypopigmented skin sunburns easily and hyperpigmented skin may get even darker.
Call your health care provider if
- there is any change in skin pigmentation that occurs without an obvious cause and is persistent.
- you notice a new mole or other growth, or an existing one has changed color, size, or appearance.
What to expect at your health care provider’s office
The medical history will be obtained and a physical examination performed.
Medical history questions documenting patchy skin color in detail may include:
- time pattern o When did it develop? o Did it develop slowly or suddenly? o Is it getting worse? How fast?
- quality o Is it a loss of pigment? o Is it a problem with the blood vessels? o What color is the affected area? o What is the normal skin color?
- location o Exactly where is the skin color changed? o Is it in more than one location?
- aggravating factors o Have you had any trauma to the skin (including sunburn or frequent sun tans)? o Are you pregnant? o What medications do you take? o What medical treatments have you had?
- other o What other symptoms are also present?
A detailed examination of the skin will be performed.
Diagnostic tests that may be performed include:
- scrapings of skin lesions
- Wood’s lamp (ultraviolet light) examination of the skin
- skin biopsy
by Janet G. Derge, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.