|Classification and external resources|
A birthmark is a benign irregularity on the skin which is present at birth or appears shortly after birth, usually in the first month. They can occur anywhere on the skin. Birthmarks are caused by overgrowth of blood vessels, melanocytes, smooth muscle, fat, fibroblasts, or keratinocytes.
Dermatologists divide birthmarks into two types. Pigmented birthmarks caused by excess skin pigment cells include moles, café-au-lait spots, and Mongolian spots. Vascular birthmarks (also called red birthmarks) are caused by increased blood vessels and include macular stains (salmon patches), hemangiomas, and Port-wine stains. A little over 1 in 10 babies have a vascular birthmark present by age 1. Several birthmark types are part of the group of skin lesions known as nevi or naevi, which means "birthmarks" in Latin.
The exact cause of most birthmarks is unknown, but vascular birthmarks are not hereditary. They are thought to occur as a result of a localized imbalance in factors controlling the development and migration of skin cells.
Pigmented types 
Mole (Congenital melanocytic nevus) 
Congenital melanocytic nevus is a type of melanocytic nevus (or mole) found in infants at birth. Occurring in about 1% of infants in the United States, it is located in the area of the head and neck 15% of the time, but may occur anywhere on the body. It may appear as light brown in fair-skinned people, to almost black in darker-skinned people. Coming in a variety of sizes and appearances, they may be irregular in shape and flat, or raised and lumpy in appearance and feel.
Café au lait spot 
Café au lait spot macules may occur anywhere on the body. They are most commonly oval in shape and light brown, or milk coffee, in color. These birthmarks may be present at birth, or appear in early childhood, and do not fade much with age. One or two on an individual is common; however, four or more may be an indicator of neurofibromatosis.
Mongolian spot (Dermal melanocytosis) 
A Mongolian blue spot is a benign flat congenital birthmark with wavy borders and irregular shape, most common among East Asians and Turks (excluding Turkish people of Asia Minor), and named after Mongolians. It is also extremely prevalent among East Africans and Native Americans. Authentic Mongolian blue spots disappear within the first four years of life. The most common color is blue, although they can be blue-gray, blue-black or even deep brown.
The Mongolian spot is a congenital developmental condition exclusively involving the skin. The blue colour is caused by melanocytes, melanin-containing cells, that are deep under the skin. Usually, as multiple spots or one large patch, it covers one or more of the lumbosacral area (lower back), the buttocks, sides, and shoulders. It results from the entrapment of melanocytes in the dermis during their migration from the neural crest to the epidermis during embryonic development.
Among those who are not aware of the background of the Mongolian spots, it may sometimes be mistaken for a bruise indicative of child abuse.
Vascular types 
Stork bite (Nevus flammeus nuchae) 
Colloquially called a "stork bite", "angel's kiss" or "salmon patch", telangiectatic nevus appears as a pink or tanned, flat, irregularly shaped mark on the knee, back of the neck, and/or the forehead, eyelids and, sometimes, the top lip. The skin is not thickened and feels no different from anywhere else on the body; the only difference remaining in appearance. Nearly half of all babies have such a birthmark.
Strawberry mark (Hemangioma) 
A hemangioma of infancy (strawberry mark) is a benign self-involuting tumor (swelling or growth) of endothelial cells, the cells that line blood vessels. It usually appears during the first weeks of life and resolves by age 10. In infancy, it is the most common tumor.
Port-wine stain (Nevus flammeus) 
Port-wine stains, sometimes mistaken for strawberry marks, are present at birth and range from a pale pink in color, to a deep wine-red. Irregular in appearance, they are usually quite large, and caused by a deficiency or absence in the nerve supply to blood vessels. This causes the blood vessels to dilate, and blood to pool or collect in the affected area. Over time, port-wine stains may become thick or develop small ridges or bumps, and do not fade with age. Such birthmarks may have emotional or social repercussions.
Port-wine stains occur in 0.3% of the population, equally among males and females. They frequently express unilaterally, i.e., on only one side, not crossing the midline of the body. Often on the face, marks on the upper eyelid or forehead may be indicative of a condition called Sturge-Weber syndrome. Additionally, port-wine stains in these locations may be associated with glaucoma and seizures.
Most birthmarks are harmless and do not require treatment. Pigmented marks can resolve on their own over time in some cases. Vascular birthmarks may require reduction or removal for cosmetic reasons. Treatments include administering oral or injected steroids, dermatological lasers to reduce size and/or color, or dermatologic surgery.
Birthmarks are called voglie in Italian, antojos in Spanish, and wiham in Arabic; all of which translate to "wishes" because, according to folklore, they are caused by unsatisfied wishes of the mother during pregnancy. For example, if a pregnant woman does not satisfy a sudden wish or craving for strawberries, it's said that the infant might bear a strawberry mark.
In Dutch, birthmarks are called moedervlekken, in Danish modermærke and in German Muttermal (mother-spots) because it was thought that an infant inherited the marks solely from the mother. The Hungarian word for any flat mole (as opposed to only congenital birthmarks), anyajegy, is also derived from this belief.
In Iranian folklore, a birthmark appears when the pregnant mother touches a part of her body during a solar eclipse.
- "birthmark" at Dorland's Medical Dictionary
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- About Mongolian Spot
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- Mongolian Spot - English information of Mongolian spot, written by Hironao NUMABE, M.D., Tokyo Medical University.
- Haggstrom AN, Drolet BA, Baselga E, et al. (September 2006). "Prospective study of infantile hemangiomas: clinical characteristics predicting complications and treatment". Pediatrics 118 (3): 882–7. doi:10.1542/peds.2006-0413. PMID 16950977.
- "Port Wine Stain Information". Vascular Birthmark Foundation. Retrieved 2008-08-02.
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