Hidradenitis suppurativa can affect one spot or multiple areas of the body. Signs and symptoms of hidradenitis suppurativa include: 1  Blackheads. Small pitted areas of skin containing blackheads â often appearing in pairs or a double-barreled pattern â are a common feature.  Red, tender bumps. These bumps often enlarge, break open and drain pus.
Sebum is an oily substance that's secreted by sebaceous glands to keep skin moisturized. Too much leads to oily skin and too little leads to dry skin. Sebum is an oily substance that's secreted by sebaceous glands to keep skin moisturized.
Acne typically appears on your face, neck, chest, back and shoulders. These areas of skin have the most oil (sebaceous) glands. Acne occurs when hair follicles become plugged with oil and dead skin cells. Hair follicles are connected to oil glands. These glands secrete an oily substance (sebum) to lubricate your hair and skin. Sebum normally travels along the hair shafts and through the openings of the hair follicles onto the surface of your skin. When your body produces an excess amount of sebum and dead skin cells, the two can build up in the hair follicles. They form a soft plug, creating an environment where bacteria can thrive.