Red bumps on the chest are considered to be caused by folliculitis, acne, urticaria, insect bite dermatitis, eczema and other causes, the specific cause of the disease should be promptly go to the hospital to confirm. 1. folliculitis: when bacteria and other pathogens infect the damaged or irritated hair follicles, it can cause inflammation of the hair follicles and the surrounding tissues, often manifested as pimples, pustules, etc., resulting in the symptom of red bumps on the chest. 2. acne: the disease is caused by excessive secretion of androgens in the body, increased sebaceous gland secretion, abnormal proliferation of keratinocytes around the hair follicles and local infections, often manifested as pimples, pimples, pustules, etc., which can lead to the symptoms of red bumps on the chest. 3. urticaria: when the body is exposed to allergens or other factors, causing local vasodilatation and increased vascular permeability, increased secretion of glands, etc., often manifested as wind, itching, etc., which can lead to the symptom of red bumps on the chest. 4. insect bite dermatitis: the disease is due to mosquito bites skin induced local skin allergic reaction, often manifested as pimples, bumps, redness and swelling, which can lead to the symptoms of red bumps on the chest. 5. eczema: the disease is caused by a variety of factors, chronic, inflammatory, itchy skin diseases, often pimples, blisters, decay, etc., if you are suffering from eczema, can be manifested as long red bumps on the chest. When the symptoms of long red bumps on the chest, you should go to the hospital in time for diagnosis, clarify the cause of the disease, and carry out targeted treatment under the guidance of professional physicians to avoid aggravation of the condition.