What is the term for a contagious skin condition caused by a fungal infection that can affect the scalp?

Ringworm is the term used to describe a contagious skin condition caused by a fungal infection, which can indeed affect the scalp. This condition is scientifically known as tinea capitis when it occurs on the scalp. Ringworm presents itself as circular, red, and itchy patches on the skin, which can lead to hair loss in the affected areas. The name "ringworm" derives from the characteristic circular, ring-like appearance of the rash.

Tinea versicolor, while also a fungal infection, is distinct from ringworm and typically affects the skin's pigmentation, leading to lighter or darker patches rather than the circular lesions associated with ringworm. Psoriasis is an autoimmune condition characterized by red, scaly patches and is not caused by a fungal infection. Dermatitis is a general term for skin inflammation and can have various causes, but it is not specifically a fungal infection like ringworm. Hence, the correct identification and terminology for this contagious fungal infection affecting the scalp is ringworm.