How is a lot of small red pimples growing on the chest to return a responsibility

If there are a lot of small red bumps on the chest, it may be that the patient has a certain allergy to this part. The most common may be allergic dermatitis or eczema. The reason for this phenomenon may be related to the patient's local exposure to allergic substances, or due to certain dietary factors leading to local allergic inflammation. It may also be caused by infectious factors, especially conditional pathogenic infections due to localized hair follicles and sebaceous glands, such as inflammatory papules showing consistent hair follicles due to Propionibacterium acnes infection, or Malassezia folliculitis due to fungal infection.