Picking off a piece of flake on the head can be considered to be related to skin lesions such as psoriasis, seborrheic dermatitis or tinea capitis. 1. Psoriasis: in addition to the scales of the skin of the body, white scales can also appear in the scalp area, which can be dispersed or fused into a piece, and the scales are dry and thick, which can go beyond the hairline and make the hair present bundled hair, and there is itching on the scalp, which can be picked off a piece of dandruff. 2. Seborrheic dermatitis: seborrheic dermatitis: seborrheic dermatitis in the scalp area or malassezia and other microbial parasites can make the scalp appear erythematous spots, and dandruff can be formed, and the hair will also fall off, thinning. 3. Tinea capitis: when the scalp area has a dermatophyte infection, it can first appear in the scalp yellowish-red spots, which can be covered with flaky scales, and can gradually form yellowish scabs, accompanied by varying degrees of scalp itching, pain, and hair loss and hair breakage. There are many reasons for picking off a piece of dandruff on the head, it is recommended to consult a doctor in time, after a clear diagnosis, follow the doctor’s instructions for treatment.