Naevus anaemicus

Naevus Anaemicus is a rare type of birthmark that is characterized by an area of skin that appears lighter than the surrounding skin. Unlike most birthmarks, which are usually pigmented, naevus anaemicus is not due to a difference in pigmentation but rather a reduction in blood flow to the affected area. This condition is congenital, meaning it is present from birth, and is considered to be a vascular anomaly.

Causes and Pathophysiology

Naevus anaemicus is caused by a localized hypersensitivity of the blood vessels (capillaries) in the affected area to the neurotransmitter norepinephrine. This hypersensitivity leads to a persistent constriction of the blood vessels, reducing blood flow to the area and resulting in the characteristic pale appearance of the skin. It is not associated with any systemic diseases and is considered to be a benign condition.

Clinical Features

The hallmark of naevus anaemicus is a pale patch of skin that does not become red or flushed under circumstances that would typically cause the surrounding skin to do so, such as physical exertion, emotional stress, or exposure to heat. This is due to the reduced blood flow to the area. The size and shape of the patch can vary significantly from person to person. Naevus anaemicus can occur anywhere on the body but is most commonly found on the trunk and limbs. It is usually asymptomatic and does not cause any discomfort.

Diagnosis

Diagnosis of naevus anaemicus is primarily clinical, based on the appearance of the skin and its response to stimuli that would normally cause flushing. A dermoscopic examination can help in visualizing the reduced blood flow in the affected area. In some cases, a skin biopsy may be performed to rule out other conditions that can cause similar patches of pale skin, but this is rarely necessary.

Treatment

No treatment is required for naevus anaemicus, as it is a benign condition that does not cause any symptoms or complications. Individuals with naevus anaemicus should be reassured about the nature of the condition. If there is concern about the cosmetic appearance, makeup can be used to cover the area.

Prognosis

The prognosis for naevus anaemicus is excellent. It does not progress or lead to any adverse health outcomes. The appearance of the birthmark may remain stable throughout life, or it may become less noticeable with age.

See Also

• Birthmark
• Vascular anomaly
• Dermoscopy

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