White patches on the back of the hands may be associated with sweat patches, vitiligo and diseases such as pityriasis simplex.
1. Sweat patches is the common name for lichen planus, which is a superficial fungal infectious diseases, in the clinical mainly manifested as round or round-like pigmentation or hyperpigmentation spots, the surface can be covered with a little scales, take the lesion parts of the skin for fungal microscopy, can be found in the mycelium or spores.
2. Vitiligo is a pigmentation loss disease, in the clinical mainly manifested in the size of the white patches, different white patches can be fused with each other, the surface of the white patches of hair can be white, Wood’s lamp examination can help to clarify the diagnosis.
3. Furfura simplex is also a kind of limited hypopigmented spots, the border is not clear, the surface can be seen furfuraceous scales. The cause of its pathogenesis is not clear, and is currently believed to be mainly related to atopic dermatitis.
Due to the complexity of the etiology, it is necessary to consult a doctor for specific cases.