Anemic nevus is a congenital limited hypopigmented spot Anemic nevus, generally unilateral distribution or confined to a certain part of the birth or soon after the occurrence, after itself rarely continue to expand, the shape is unchanged, the color for the hypopigmentation rather than pigmentation loss, rubbing or heating, the local area does not redden, while the surrounding normal skin reddening, with the slide diagnostic compression, the edges of the skin lesions are more ambiguous. According to the above characteristics can be identified with vitiligo. Editorial features For the limited skin light-colored spots, the vascular tissue in the place of the developmental defects, but not structural but functional abnormalities. Neurofibroma patients complicate this disease more often than normal people. Edit This section Etiology This disease is caused by the increased sensitivity of blood vessels to catecholamines, while the local blood vessels are always in a state of constriction, so that the local skin ischemia and white patches occur. Edit This section Clinical symptoms It occurs after birth or during childhood, or it can occur later, with equal incidence in both sexes. It occurs on the face, neck or buttocks. It occurs unilaterally, and the lesions are light-white patches with unclear boundaries and irregular morphology, with no change in skin texture. They are single or multiple round, ovoid or irregularly shaped light-colored spots. When pressed with a slide, it is not easy to distinguish from the surrounding whitened skin; or when rubbed with the palm of the hand, the surrounding skin is red, while the light-colored spots are not red. The disease can occur in any part of the body, but the trunk is more common. It does not subside throughout life. The anemic nevus is heavy and obvious in winter and light and inconspicuous in summer. Edit This paragraph Pathological changes There are no abnormal tissue changes, but rather a functional abnormality with increased local vascular reactivity to catecholamines and vasoconstriction of the blood vessels. Edit This paragraph Prevention and treatment The anemic nevus can be externally applied to make vasodilatory drugs, such as 5% capsaicin ointment. Edit this paragraph Differential diagnosis Anemic nevus is similar to vitiligo and achromatic nevus. Their respective characteristics are as follows: Vitiligo is clearly distinguishable from normal skin tissues, the color of its surrounding skin is obviously aggravated, and the border of the white spot will be more clear when a clean slide is pressed vertically downward.　Anemic nevus is just the opposite of vitiligo. Anemic nevus is only limited hypopigmentation, not pigmentation loss, therefore, there is no obvious boundary between the area under pressure and the normal skin, and the area of the anemic nevus has obvious "dendritic texture", and the anemic nevus does not have the tendency to expand, and the local area does not redden when rubbing the lesion with force while the normal skin around it reddens. When a slide is pressed down, the nevus disappears.　Anaplastic nevus is equivalent to a certain area of abnormal melanin development, for the congenital formation, but not immediately after birth can be manifested, which is with vitiligo easy to confuse the reason. Vitiligo grows more randomly, with the change of seasons the area will be different, after regular treatment can also shrink. And once formed, the size of the unpigmented nevus is basically fixed, and its development speed and enlargement speed is directly proportional to the body development.