Dandruff that keeps returning for many years is often related to chronic seborrheic dermatitis, excess scalp oil, fungal overgrowth, stress, sweating, or scalp sensitivity. Even when shampoos or antifungal medicines help temporarily, the condition may come back because the scalp inflammation and oil imbalance continue underneath. Repeated flare-ups are common in long-standing dandruff problems. Treatment usually works better with regular maintenance, rather than stopping treatment completely once the flakes improve. Anti-dandruff shampoos containing ketoconazole, zinc carbonate, zinc pyrithione or salicylic acid may help when rotated properly and consistently. Leave the shampoo on the scalp for a few minutes before rinsing can improve control of thick flakes and oil buildup. Good sleep, stress reduction, regular scalp washing, and avoiding heavy oil application may also reduce recurrence. Long-term use of strong medicines without supervision may irritate the scalp or affect hair quality. Thick, greasy scales, scalp redness, painful bumps, or increasing hair thinning can sometimes happen when scalp inflammation becomes more active and may need stronger scalp-focused treatment.