The causes of bald patch in the middle of hairline may be baldness, seborrheic alopecia, hair follicle disease and so on. 1. Pemphigus: Pemphigus can occur in any part of the scalp, and occurring in the middle of the hairline will lead to a bald patch in the middle of the hairline, which can be caused by mental factors, hereditary factors, allergic factors and so on. 2. Seborrheic alopecia: Seborrheic alopecia can also cause hair loss in the middle of the hairline, shedding and baldness, which is more common in males, and at the same time, there can be a frontal hairline moving back, greasy hair, dandruff increase and so on. 3. Hair follicle disease: such as folliculitis, the pathogenic bacteria if the scalp invasion, after the healing legacy of scar formation, may cause permanent hair loss. Therefore, there are more reasons for baldness in the middle of the hairline, and patients should consult the doctor in time for early treatment, so as not to delay the condition and affect the prognosis.