Before knowing whether hair oil increases dandruff, let's know a little about why dandruff occurs. Dandruff is a common inflammatory scalp condition. It can range from mild to severe. Especially Seborrhoeic Dermatitis (Seborrhoeic Dermatitis) or fungal causes are responsible for causing this problem. The cells on our scalp regenerate every month. That is, new cells rise up from deep within the scalp and old ones are shed. If these shedding cells are not cleaned, dandruff is formed. Dandruff problems are common in winter, but many people suffer throughout the year.