Nevus anemicus
Encyclopedia
Nevus anemicus is a congenital disorder characterized by macules of varying size and shape that are paler than the surrounding skin and cannot be made red by trauma, cold, or heat. The paler area is due to the blood vessels within the area which are more sensitive to the body’s normal vasoconstricting chemicals.
patch appears on the skin at birth or in early childhood. In most people these are under 10cm
in size. If there is doubt about the diagnosis, rubbing the area causes the skin around the lesion to become red while the lesion itself does not change in color. Often the patches are difficult to see against the background color of the patient’s skin, but if sunburn
develops, then the white area stands out prominently. The involved area is lighter than the normal skin, not because of a loss of pigment occurs, but because blood vessels are constricted, producing a perment blanching of the area. This blanching is a functional rather than a structual abnormality, presumed to be caused by local increased sensitivity to catecholamines
. Although the cutaneous vasculature
appears normal histologically, the blood vessels within the nevus do not respond to injection of vasodilators. It has been postulated that the persistent pallor may represent a sustained localized adrenergic vasoconstriction
. Results of a skin biopsy
would be interpreted as normal and only physiological testing can reveal the nevus in contrast to normal skin. Stroking the patch elicits no red flare. Only the normal skin would react with a characteristic erythematous response. Examination under a Wood lamp can also reveal the nevus anemicus patch will not emphasize as a patch of vitiligo
would.
of nevus anemicus is normal, nevus anemicus is a pharmacologic nevus and not an anatomic one. and in most people a nevus anemicus is on a covered area and so light in appearance that no treatment is needed.
Symptoms
This benignBenign
A benign tumor is a tumor that lacks the ability to metastasize. Common examples of benign tumors include moles and uterine fibroids.The term "benign" implies a mild and nonprogressive disease. Indeed, many kinds of benign tumors are harmless to human health...
patch appears on the skin at birth or in early childhood. In most people these are under 10cm
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...
in size. If there is doubt about the diagnosis, rubbing the area causes the skin around the lesion to become red while the lesion itself does not change in color. Often the patches are difficult to see against the background color of the patient’s skin, but if sunburn
Sunburn
A sunburn is a burn to living tissue, such as skin, which is produced by overexposure to ultraviolet radiation, commonly from the sun's rays. Usual mild symptoms in humans and other animals include red or reddish skin that is hot to the touch, general fatigue, and mild dizziness. An excess of UV...
develops, then the white area stands out prominently. The involved area is lighter than the normal skin, not because of a loss of pigment occurs, but because blood vessels are constricted, producing a perment blanching of the area. This blanching is a functional rather than a structual abnormality, presumed to be caused by local increased sensitivity to catecholamines
Catecholamine
Catecholamines are molecules that have a catechol nucleus consisting of benzene with two hydroxyl side groups and a side-chain amine. They include dopamine, as well as the "fight-or-flight" hormones adrenaline and noradrenaline released by the adrenal medulla of the adrenal glands in response to...
. Although the cutaneous vasculature
Circulatory system
The circulatory system is an organ system that passes nutrients , gases, hormones, blood cells, etc...
appears normal histologically, the blood vessels within the nevus do not respond to injection of vasodilators. It has been postulated that the persistent pallor may represent a sustained localized adrenergic vasoconstriction
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
. Results of a skin biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
would be interpreted as normal and only physiological testing can reveal the nevus in contrast to normal skin. Stroking the patch elicits no red flare. Only the normal skin would react with a characteristic erythematous response. Examination under a Wood lamp can also reveal the nevus anemicus patch will not emphasize as a patch of vitiligo
Vitiligo
Vitiligo is a condition that causes depigmentation of sections of skin. It occurs when melanocytes, the cells responsible for skin pigmentation, die or are unable to function. The cause of vitiligo is unknown, but research suggests that it may arise from autoimmune, genetic, oxidative stress,...
would.
Treatment
Since the histopathologyHistopathology
Histopathology refers to the microscopic examination of tissue in order to study the manifestations of disease...
of nevus anemicus is normal, nevus anemicus is a pharmacologic nevus and not an anatomic one. and in most people a nevus anemicus is on a covered area and so light in appearance that no treatment is needed.