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.
Sebum is found on the outermost layer of skin. Sebum moistens, or lubricates (say: LOO-bruh-kates), and protects your skin. It also makes your skin a bit waterproof. That's why water runs off your skin when you wash your hands, instead of soaking it in like a sponge would. But staying in water for a long time washes away the sebum. Then, the water can penetrate the outer layer of your skin. This causes your skin to become waterlogged.