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.
[James, William; Berger, Timothy; Elston, Dirk (2005). ''Andrews' Diseases of the Skin: Clinical Dermatology''. (10th ed.). Saunders. Page 582. .] The paler area is due to the blood vessels within the area which are more sensitive to the body’s normal vasoconstricting chemicals.
Signs and symptoms
This
benign
Malignancy () is the tendency of a medical condition to become progressively worse.
Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...
patch appears on the skin at birth or in early childhood. In most people these are under 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 is a form of radiation burn that affects living tissue, such as skin, that results from an overexposure to ultraviolet (UV) radiation, usually from the Sun. Common symptoms in humans and animals include: red or reddish skin that is ho ...
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 permanent blanching of the area. This blanching is a functional rather than a structural abnormality, presumed to be caused by local increased sensitivity to
catecholamine
A catecholamine (; abbreviated CA) is a monoamine neurotransmitter, an organic compound that has a catechol (benzene with two hydroxyl side groups next to each other) and a side-chain amine.
Catechol can be either a free molecule or a subst ...
s.
[McMillan, Julia A; DeAngelis, Catherine D.; Feigin, Ralph D.; Warshaw, Joseph B. (2006). ''Oski's Pediatrics, Principles & Practice''. (4th ed.). Page 458. .] Although the cutaneous
vasculature
The blood circulatory system is a system of organs that includes the heart, blood vessels, and blood which is circulated throughout the entire body of a human or other vertebrate. It includes the cardiovascular system, or vascular system, tha ...
appears normal
histologically
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single ...
, the blood vessels within the nevus do not respond to injection of
vasodilators
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstriction, ...
. It has been postulated that the persistent pallor may represent a sustained localized adrenergic
vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessel ...
.
[Nelson Textbook of Pediatrics 19th. (10th ed.). W.B. Saunders Company. Page 640. .] Results of a skin
biopsy
A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a diseas ...
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 is a disorder that causes the skin to lose its color. Specific causes are unknown but studies suggest a link to immune system changes.
Signs and symptoms
The only sign of vitiligo is the presence of pale patchy areas of depigmen ...
would.
[Barber Kirk (2010). Consultant For Pediatricians '. Page 9:233, 237.]
Diagnosis
Treatment
Since the
histopathology
Histopathology (compound of three Greek words: ''histos'' "tissue", πάθος ''pathos'' "suffering", and -λογία '' -logia'' "study of") refers to the microscopic examination of tissue in order to study the manifestations of disease. Spe ...
of nevus anemicus is normal, nevus anemicus is a
pharmacologic nevus and not an
anatomic
Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its ...
one.
[Mountcastle EA, Diestelmeier MR, Lupton GP. Nevus anemicus. J Am Acad Dermatol 1986;14:628-32..][Requena L, Sangueza OP. Cutaneous vascular anomalies. Part 1. Hamartomas, malformations and dilation of preexisting vessels. J Am Acad Dermatol 1997;37:523-49, quiz 549-52.] In most people a nevus anemicus is on a covered area and so light in appearance that no treatment is needed.
See also
*
List of cutaneous conditions
Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against t ...
*
Melanism
The term melanism refers to black pigment and is derived from the gr, μελανός. Melanism is the increased development of the dark-colored pigment melanin in the skin or hair.
Pseudomelanism, also called abundism, is another variant of pi ...
*
Nevus
Nevus (plural nevi) is a nonspecific medical term for a visible, circumscribed, chronic lesion of the skin or mucosa. The term originates from ''nævus'', which is Latin for "birthmark"; however, a nevus can be either congenital (present at bir ...
*
Skin lesion
A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of this s ...
References
{{Pigmentation disorders
Disturbances of human pigmentation