Ringworm of the Scalp, called Tinea Capitis in medical terminology, is the same fungus that causes “athlete’s foot,” “jock itch,” and ringworm of the body in general. It almost only occurs on the heads of children, where it causes one or several patches of hair loss with scaly skin. Sometimes there are black dots, which are tiny stubs of broken hairs. Diffuse hair loss with scaly scalp is uncommon, and would suggest the condition Seborrheic Dermatitis. A severe form of Tinea Capitis is a kerion, a boggy, crusted plaque which is often tender.
It’s common for such fungal infections to cause swollen lymph nodes nearby, on the back of the head or neck. A strange but not rare accompaniment to fungal infections is an “id” reaction: an immune inflammatory response causing tiny blisters, scales, or pimples on the face, body or hands. This is more common after treatment is begun, and resolves on its own; it is not an “allergy.”
Clinicians can diagnose Tinea Capitis by preparing a slide of scraped skin and plucked hairs, adding potassium hydroxide and viewing it under a microscope. It’s easy to identify fungi. This is most useful for adults, who rarely get the condition unless they are fairly immunocompromised.
Anti-fungal creams don’t work for Tinea Capitis, the way they do for ringworm elsewhere on the body. Treatment needs to be given orally.