The reasons that you get acne on the chest are the same as the causes for acne in other parts of the body. It is well understood that the sebaceous glands beneath the skin surface that produces oil and the dead skin cells that are emitted are washed off during baths and washing of face and other parts of the body. However overproduction of oils block the natural skin pores and provide for favorable living conditions for the bacteria Propionibacterium acnes that grows on the skin as acne and pimples.
It is to be understood that the prominent causes for acne on chest are hormonal imbalances, excessive sports, the excessive use of deodorant, body powders and lotions, and the summer season when one tends to perspire more and use these products.