Which of the following is a common scalp disorder?

Dandruff is considered a common scalp disorder because it affects a significant number of individuals and is characterized by the flaking of skin on the scalp. It can be caused by a variety of factors, including dry skin, sensitivity to hair products, or a condition known as seborrheic dermatitis, which leads to an overproduction of oil on the scalp.

Dandruff typically presents as white or yellow flakes and may be accompanied by itching. It is particularly common in adults and can be influenced by environmental factors or health conditions. The prevalence and simplicity of diagnosis make it a widely recognized scalp issue compared to other disorders, which may not be as common or are often more complex in nature.

While psoriasis, acne, and fungal infections are also skin-related conditions, they are not classified as common scalp disorders to the same extent as dandruff. Psoriasis is usually more widespread and can affect other areas of the body significantly. Acne typically occurs on the face, back, and shoulders rather than primarily on the scalp, and fungal infections, while they can affect the scalp, are less frequently encountered in the general population compared to dandruff.