The pimples on the back of the head are generally considered to be caused by folliculitis, but eczema, seborrheic dermatitis, etc. may also occur in patients with pimples on the back of the head. 1, folliculitis: inflammatory skin disease in which the hair follicles are mainly involved, mostly due to inflammation around the mouth of the hair follicles due to the invasion of purulent cocci, confined to the upper part of the hair follicles. It is often manifested as a red papule or pustular rash centered on the hair follicle, which may be itchy and painful, or may not feel anything; 2. Eczema: mainly due to allergies, generally manifested as a red papule-like pimple, the lesions may be accompanied by exudation, this situation should first pay attention to avoid allergens, the use of anti-allergy medication, along with local topical treatment, such as boric acid solution; 3. Seborrheic dermatitis. The developed parts of the sebaceous glands are prone to excessive accumulation of fatty secretions, which can induce seborrheic dermatitis, manifesting as erythematous rash-like acne, which occurs in the head; 4, endocrine disorders: acne behind the head is also related to endocrine disorders caused by personal bad habits, bad eating habits or mental stress, etc. It is recommended that we all develop good habits, pay attention to a balanced diet, and relax ourselves at the right time. The first thing you need to do is to take care of yourself.