What causes white spots on thigh skin?

White spots are white spots, which may be partially white or small white dots. Many people do not have a comprehensive understanding of white spots. Not all white spots are vitiligo. The appearance of white spots on the thigh skin is related to many factors and may also be caused by other skin diseases.

1. Vitiligo.

Vitiligo is a common acquired skin depigmentation disease. The surface of the white spots on the affected area is smooth and free of dandruff, and is light white or milky white in color. The pigmentation at the edges is increased compared to normal skin, and the hair inside the white spots is normal or whitened. The lesions often occur in areas exposed to sunlight and damaged by friction, and are often distributed symmetrically. White spots are often distributed according to nerve segments and arranged in bands. In addition to skin lesions, the mucous membranes of the lips, labia, glans penis and inner foreskin are also often affected. Most patients have no subjective symptoms, and a small number of patients experience local itching in the affected area before or during the onset of the disease. There is no significant difference in the gender of patients. The disease can occur in all age groups, but it is more common in adolescents.

2. Pityriasis versicolor.

Pityriasis versicolor, also known as pityriasis versicolor, is a chronic disease with usually no symptoms. The disease is characterized by scattered or fused hypopigmented or hyperpigmented macules with bran-like desquamation, which often occurs on the chest, back, upper arms, axillae, and sometimes the face. The initial lesions are circular punctate macules surrounding the pores, which gradually increase to the size of a nail plate with clear edges. Adjacent areas may merge into large irregular patches, with new macules appearing around them. The surface is covered with a small amount of bran-like scales that are easily peeled off, ranging from gray, brown to yellow-brown, and sometimes multiple colors coexist, resembling spots. The longer the time, the lighter the spots.

3. Simple pityriasis.

This disease is also known as pityriasis alba. The typical skin lesions are round or oval pink spots with blurred edges, with a diameter of 0.5 to 2.0 cm or larger. After a few weeks, the pale red spots gradually turn into pale white spots, covered with a small amount of bran-like scales. The number of lesions varies, mainly on the face and occasionally on other parts of the body. No subjective symptoms, or there may be itching or burning sensation. The course of the disease varies in length, worsening in summer, but it can all resolve naturally.

4. No pigmented mole.

Also known as depigmented nevus, it is a rare, congenital, localized white spot. The disease occurs at birth or shortly after birth. The white spots can expand proportionally with the development of the body. The pigment in the depigmented area will not regenerate, so it cannot disappear naturally. Skin lesions often occur on the trunk, lower abdomen, proximal limbs, and may also be affected on the face and neck. If the damage occurs in the trigeminal nerve area, it may be accompanied by neurological symptoms and epilepsy. There is currently no effective drug treatment for this disease. If it is necessary for cosmetic reasons, skin lesions on exposed areas can be covered. In adulthood, autologous epidermal transplantation can be performed.