Seborrheic dermatitis is a scalp condition where excess oil, fungal overgrowth and skin inflammation cause thick scales, itching, redness and stubborn dandruff-like flakes. The scales may stick tightly to the scalp and return repeatedly, particularly during stress, sweating, poor sleep, weather changes or irregular hair washing. Some people also notice increased hair shedding due to constant scalp inflammation. Treatment usually focuses on reducing scalp fungus, softening thick scales and soothing inflammation. Anti-dandruff shampoos with ketoconazole, selenium disulfide, zinc pyrithione, coal tar or salicylic acid are commonly used to loosen scales and reduce itching. Leave the shampoo on the scalp for several minutes before washing may improve results. In stronger flare-ups, doctors sometimes prescribe medicated scalp lotions or short-term anti-inflammatory treatments to reduce redness and irritation. Avoid forcefully scratching thick scales, as this could injure the scalp and worsen inflammation. Painful scalp swelling, pus-filled bumps, bleeding patches or rapidly increasing hair loss can suggest more active scalp inflammation and may require suitable treatment for better control.