There are many reasons for itchy forehead, the common ones are allergic dermatitis, seborrheic dermatitis, psoriasis and other physical factors. 1. Allergic dermatitis: the most common cause, some cosmetics, skin care products may contain irritating ingredients or sensitizing ingredients, will stimulate the skin symptoms of allergic dermatitis, skin itching. 2. Seborrheic dermatitis: the skin at the forehead is more exuberant in oil secretion, and it is easy to suffer from seborrheic dermatitis. Usually, the skin at the affected area will be itchy, erythematous, and flaky skin flakes, which are greasy white or light yellow. 3. Psoriasis: Scalp psoriasis can be manifested as a varying number of red plaques on the scalp, scalp and forehead where the skin is often itchy to varying degrees. 4. Other: sunburn, hats and turbans and other hair accessories stimulation, work stress, systemic diseases such as diabetes, liver and kidney disease can also cause itchy skin at the forehead. There are many reasons for forehead itching, first of all, patients need to do a good job of local skin cleaning, if the symptoms do not go away, you need to go to the hospital in a timely manner, after a clear cause of targeted treatment.