Tinea capitis and seborrheic dermatitis are both skin diseases, but they are very different.

Firstly, the types of fungi that cause tinea capitis and seborrheic dermatitis are different. Tinea capitis is mainly caused by fungi such as Trichophyton violaceum and Trichophyton tonsurans, whereas seborrheic dermatitis is predominantly caused by Malassezia.

Secondly, their clinical manifestations are also different. The clinical manifestations of seborrheic dermatitis are often less severe than those of tinea capitis.

Finally, tinea capitis often does not heal by itself and requires professional treatment, while seborrheic dermatitis can heal on its own, but tends to recur frequently.