What fungus is primarily responsible for dandruff?

The fungus primarily responsible for dandruff is Malassezia. This genus of yeast-like fungi is naturally present on the scalp and often thrives in conditions of oiliness, which can increase its growth. When the Malassezia populations grow excessively, they can trigger an inflammatory response in the skin, leading to the symptoms associated with dandruff, such as flaking and itching.

To further understand why Malassezia is the correct choice: it is an opportunistic organism that can cause irritation and sensitivity in some individuals, contributing to the flaking seen in dandruff. Other choices are not directly responsible for dandruff. Pityriasis Steatoides is a condition related to seborrheic dermatitis, which sometimes overlaps with dandruff but is not a fungus itself. Staphylococci refer to a type of bacteria that can cause various infections but are not involved in dandruff. Pediculosis Capitis refers to head lice infestation, which has entirely different causes and symptoms compared to dandruff. This context emphasizes why Malassezia is the key player in dandruff.