First of all, scalp fungus or ringworm can be confined to just the scalp of the head .
Secondly, in the US the most common fungus is Trichophyton tonsurans. It starts often in a subtle way and in the beginning resembles dandruff. In other countries the Microsporum species of fungal scalp infections are more common.
Third, the dermatologist can distinguish between the two using Wood’s light as the hair fluoresces when Microsporum, which multiplies outside the hairs, is involved, whereas it does not fluoresce with Trichophytum, where the spores grow inside the hairs.
Likewise, in the link above you can clearly appreciate the patch of whitish fluorescing lesion on the left side in the otherwise blue light of Wood’s light.
Scalp Fungus (Tinea Capitis)
The doctor can remove a few skin flakes and stain the Microsporum fungus. This demonstrates that the fungus is present in this infected skin patch. Here is another image of a tinea capitis lesion that has been neglected for several months, perhaps years.
Treatment
The treatment for children with Trichophyton involves a course of 4 weeks with oral suspension of griseofulvin with meals or milk until the scalp infection resolves entirely. Parallel to this the doctor may prescribe Loprox cream, which the patient applies to the scalp. In other patients the doctor may order selenium sulfide (brand name: Versel lotion) to wash the hair daily.
References
1.The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 265.
2.James Chin et al., Editors: Control of Communicable Diseases Manual, 17th edition, 2000, American Public Health Association
3.The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 112.
4. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 115.
5. The Merck Manual, 7th edition, by M. H. Beers et al., Whitehouse Station, N.J., 1999. Chapter 113.
