Should be distinguished from the following diseases: 1, seborrheic dermatitis The edge of the damage is not obvious, the basal infiltration is lighter, the scales on the rash are furfuraceous, no Ausspitz’s sign, seborrheic dermatitis in the scalp area is often accompanied by hair loss, the hair is not in bundles. 2, pityriasis rosea damage mainly occurs in the trunk and the proximal extremities, the long axis of the rash is consistent with the skin pattern. The scales are fine and thin. The course of the disease is short, not easy to recur after healing. 3, flat moss damage occurs mostly in the extremities, for purplish red polygonal flat papules, the surface has wax-like luster. Wickham lines can be seen. Oral cavity is often damaged, often with varying degrees of itching, histopathology with specificity. 4, hair red furunculosis damage occurs more in the extensor side of the limbs, early for follicular keratosis papules, in late patches of skin lesions around can still see follicular keratosis papules. In particular, the papules of follicular keratosis of the first phalanx are characteristic of this disease. The lesions are covered with fine scales that do not easily peel off. It is often accompanied by palmoplantar hyperkeratosis. 5, parapsoriasis The damage is covered with fine scales, no multilayer scales, no film phenomenon, no Auspitz’s sign, and mostly no conscious symptoms.