Red bumps on forehead may be folliculitis, acne, insect bite dermatitis, eczema and so on. 1. Folliculitis: local hair follicles are infected by external pathogenic bacteria that can cause an inflammatory reaction of the hair follicles, resulting in red bumps on the forehead, most of which are accompanied by symptoms such as swelling and pain. 2. Acne: abnormal secretion of androgens, hypersecretion of sebaceous glands, hyperkeratosis of the epithelium of the hair follicles, Propionibacterium acnes infection can cause chronic inflammation of the sebaceous glands of the hair follicles, causing red bumps on the forehead. 3 insect bite dermatitis: due to mosquito bites, resulting in local skin edema erythema, the center can be seen pimples, can also cause red bumps on the forehead. 4. eczema: due to internal and external factors stimulation of the inflammatory reaction, may also lead to the symptoms of red bumps on the forehead. Red bumps on the forehead, there may be other reasons, you need to go to the hospital in time to check, clear cause and follow the doctor’s instructions for treatment.