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.
Since the yeast feeds on sebum (your skin's natural oils), seborrheic dermatitis is more common in people who have oily skin and most often occurs in areas where the greatest concentration of oil glands are located: the ears, eyebrows, sides of the nose, and/or scalp.