Doctors use specific terms to describe various types of marks and growths on the skin. Some skin disorders and infections can cause color changes in the skin.
(See also Structure and Function of the Skin Structure and Function of the Skin The skin is the body’s largest organ. It serves many important functions, including Protecting the body against trauma Regulating body temperature Maintaining water and electrolyte balance Sensing... read more .)
Types of Skin Marks and Growths
Atrophy is thinning of the skin that can sometimes result in a depression and often has a dry and wrinkled "cigarette paper" appearance.
Bullae are clear fluid-filled blisters that are greater than 10 millimeters (0.4 inch) in diameter (larger than vesicles).
Crusts (scabs) are dried blood, pus, or skin fluids on the surface of the skin. A crust can form wherever the skin has been damaged.
Cysts are thin-walled cavities filled with liquid or semi-liquid material. They often look and feel like a lump (nodule) in the skin.
Erosions are open areas of skin that result from loss of part or all of the top layers ( epidermis Epidermis The skin is the body’s largest organ. It serves many important functions, including Protecting the body against trauma Regulating body temperature Maintaining water and electrolyte balance Sensing... read more ) of the skin. Erosions occur when infection, pressure, irritation, or temperature has damaged the skin. They typically heal without scarring.
Excoriations are erosions caused by scratching, rubbing, or picking at the skin. Often, excoriations are covered with a crust.
Lesion is a general term for any abnormal mark or growth on the skin.
Lichenification is thickened skin that has accentuated skinfolds or creases that appear as deep grooves and wrinkles. Lichenification is caused by repeated scratching or rubbing.
Macules are flat, discolored spots of any shape less than 10 millimeters (0.4 inch) in diameter. Freckles, flat moles, port-wine stains, and many rashes are macular.
Nodules are solid raised areas that are usually round. They are deeper and easier to feel than papules. A nodule sometimes appears to form below the surface of the skin and press upward.
Papules are raised solid bumps less than 10 millimeters (0.4 inch) in diameter. Warts Warts Warts (verrucae) are small skin growths caused by human papillomavirus infection. Warts are caused by human papillomaviruses. Raised or flat growths appear on any part of the skin. Most warts... read more , insect bites Insect Bites Among the more common biting insects in the United States are the following: Sand flies Horseflies Deerflies Blackflies read more , lichen planus Lichen Planus Lichen planus, a recurring itchy disease, starts as a rash of small, separate, red or purple bumps that then combine and become rough, scaly patches. The cause may be a reaction to certain drugs... read more , and some skin cancers Overview of Skin Cancer Skin cancer is the most common type of cancer. Skin cancer is most common among people who work or play sports outside and among sunbathers. Fair-skinned people are particularly susceptible... read more can grow as papules.
Patches are larger flat spots (greater than 10 millimeters).
Plaques are flat or raised areas or groups of small bumps (papules) typically more than 10 millimeters (0.4 inch) in diameter.
Pustules are fluid-filled spots (vesicles) containing pus.
Scales are areas of heaped-up, dead epidermal cells that appear as a flaky, dry patch. Scales occur with psoriasis Psoriasis Psoriasis is a chronic, recurring disease that causes one or more raised, red patches that have silvery scales and a distinct border between the patch and normal skin. A problem with the immune... read more , seborrheic dermatitis Seborrheic Dermatitis Seborrheic dermatitis is chronic inflammation that causes yellow, greasy scales and dandruff to form on areas of the skin that have a high number of oil glands such as the scalp and face, along... read more , and many other disorders.
Scars are areas where normal skin has been replaced by fibrous (scar-forming) tissue. Scars form after damage of the dermis Dermis The skin is the body’s largest organ. It serves many important functions, including Protecting the body against trauma Regulating body temperature Maintaining water and electrolyte balance Sensing... read more .
Telangiectases are dilated blood vessels near the surface of the skin that often have a twisted appearance and that whiten (blanch) when pressure is applied.
Ulcers are similar to erosions, only deeper, penetrating at least part of the dermis. The causes are the same as for erosions, but conditions that impair healing, such as venous stasis Infectious problems in diabetes People with diabetes mellitus have many serious long-term complications that affect many areas of the body, particularly the blood vessels, nerves, eyes, and kidneys. (See also Diabetes Mellitus... read more , diabetes Complications of Diabetes Mellitus People with diabetes mellitus have many serious long-term complications that affect many areas of the body, particularly the blood vessels, nerves, eyes, and kidneys. (See also Diabetes Mellitus... read more , peripheral artery disease Overview of Peripheral Arterial Disease Peripheral arterial disease results in reduced blood flow in the arteries of the trunk, arms, and legs. Most often, doctors use the term peripheral arterial disease to describe poor circulation... read more , and vasculitis Overview of Vasculitis Vasculitic disorders are caused by inflammation of the blood vessels (vasculitis). Vasculitis can be triggered by certain infections or drugs or can occur for unknown reasons. People may have... read more , are also often involved. Ulcers usually heal with scarring.
Vesicles are small, clear fluid-filled blisters less than 10 millimeters (0.4 inch) in diameter. Bullae are vesicles larger than 10 millimeters in diameter. Herpes zoster ( shingles Shingles Shingles is a painful skin rash caused by a viral infection that results from reactivation of the varicella-zoster virus, the virus that causes chickenpox. What causes the virus to reactive... read more ), chickenpox Chickenpox Chickenpox is a highly contagious viral infection with the varicella-zoster virus that causes a characteristic itchy rash, consisting of small, raised, blistered, or crusted spots. Chickenpox... read more , burns Burns Burns are injuries to tissue that result from heat, electricity, radiation, or chemicals. Burns cause varying degrees of pain, blisters, swelling, and skin loss. Small, shallow burns may need... read more , allergic reactions Overview of Allergic Reactions Allergic reactions (hypersensitivity reactions) are inappropriate responses of the immune system to a normally harmless substance. Usually, allergies make people sneeze; the eyes water and itch... read more , and irritations form vesicles and bullae.
Wheals (hives, urticaria) are elevated, itchy, red areas that are caused by swelling in the skin. Wheals appear relatively suddenly and then almost always disappear within 24 hours. Wheals are common allergic reactions to drugs, insect bites, or something that touches the skin. The presence of multiple wheals is called hives Hives Hives are red, itchy, slightly elevated swellings. The swelling is caused by the release of chemicals (such as histamine) from mast cells in the skin, which cause fluid to leak out of small... read more or urticaria.
Color Changes in the Skin
Although certain color changes are typical, the natural color of a person's skin can change the appearance of these colors.
Red skin (erythema) can result from many different disorders that cause inflammation or are caused by infection. Tumors on the skin are often pink or red. Disorders affecting blood vessels near the skin surface, such as port-wine stains Port-Wine Stains Port-wine stains are flat pink, red, or purplish discolorations present at birth due to malformed blood vessels. (See also Overview of Skin Growths and Overview of Growths and Malformations... read more , may appear red.
Orange skin is most often the result of hypercarotenemia. Hypercarotenemia is a condition that is the result of too much of the pigment carotene in the blood. People who overeat foods rich in beta-carotene, such as carrots, may develop hypercarotenemia.
Yellow skin may occur in people who have jaundice Jaundice in Adults In jaundice, the skin and whites of the eyes look yellow. Jaundice occurs when there is too much bilirubin (a yellow pigment) in the blood—a condition called hyperbilirubinemia. (See also Overview... read more . Causes of isolated yellow areas include xanthelasmas Xanthelasma Noncancerous (benign) and cancerous (malignant) growths can form on the eyelids. A yellow-white lump known as xanthelasma is seen under the eye. This finding may indicate elevated cholesterol... read more and xanthomas (small yellow deposits of fat in the skin or tendons) and pseudoxanthoma elasticum Pseudoxanthoma Elasticum Pseudoxanthoma elasticum is a rare hereditary disorder of connective tissue that causes abnormalities in the skin, eyes, and blood vessels. Connective tissue is the tough, often fibrous tissue... read more .
Green fingernails Green Nail Syndrome Green nail syndrome is infection with Pseudomonas, a type of bacteria. (See also Overview of Nail Disorders.) The photo on the left shows green nail syndrome with onycholysis of the fourth... read more are typically caused by infection with the bacteria Pseudomonas aeruginosa.
Violet skin may be caused by bleeding beneath the skin (cutaneous hemorrhage) or vasculitis Overview of Vasculitis Vasculitic disorders are caused by inflammation of the blood vessels (vasculitis). Vasculitis can be triggered by certain infections or drugs or can occur for unknown reasons. People may have... read more . Abnormal overgrowths of blood vessels, such as Kaposi sarcoma Color Changes in the Skin and hemangiomas Hemangiomas Hemangiomas are abnormal overgrowths of blood vessels that can appear as red or purple lumps in the skin and on other parts of the body. (See also Overview of Skin Growths and Overview of Growths... read more , can appear purple. Skin inflammation due to dermatomyositis Autoimmune Myositis Autoimmune myositis causes inflammation and weakness in the muscles (polymyositis) or in the skin and muscles (dermatomyositis). Muscle damage may cause muscle pain and muscle weakness may cause... read more may cause a reddish purple or lilac color around the eyes and face (called a heliotrope rash).
Shades of blue, silver, and gray can occur when drugs or metals, including minocycline, amiodarone, and silver (argyria), are deposited in the skin. Skin that has a blocked or poor supply may appear purple to gray in color. Some birthmarks and moles Moles Moles are small, usually dark, skin growths that develop from pigment-producing cells in the skin (melanocytes). Most people have some moles, but the tendency to develop atypical moles is sometimes... read more (nevi) that are deep in the skin may appear blue.
Black skin lesions may contain specialized cells that produce the brown pigment melanin (melanocytes). Examples of these types of lesions include moles (nevi) and melanoma Melanoma Melanoma is a skin cancer that begins in the pigment-producing cells of the skin (melanocytes). Melanomas can begin on normal skin or in existing moles. They may be irregular, flat or raised... read more . Thick, black, crusty scabs (called eschars) are collections of dead skin and can be caused by death of tissue (infarction).