The only place online that list the many uses is earthclinics and the sites that keep quoting them. No one else supports this idea
*sigh*
http://www.taoofherbs.com/articles/69/Boric_Acid_Suppositories_And_Yeast_Infection.htm
http://www.epa.gov/oppsrrd1/REDs/factsheets/0024fact.pdf
http://npic.orst.edu/factsheets/borictech.pdf
AN OUTLINE OF TREATMENT FOR TINEA CAPITIS
DUE TO MICROSPORON LANOSUM
1. Clip hair as short as possible, and repeat as
often as needed until cured. This facilitates application
of local therapy and exposes small infected
foci which may be overlooked.
2. Shampoo scalp daily. This helps remove loose
infected hairs.
3. Apply a fungicide to scalp twice daily. Halfstrength
Whitfield's ointment is suggested.
4. Epilate infected patches with epilating forceps
or adhesive tape. This is most important, as
it removes the loose infected hairs. (Adhesive tape
is simple to use, quicker and more effective than
manual epilation with the forceps.)
5. The child should wear a paper cap which can
be burned or one of cloth that can be boiled. These
caps should be changed daily.
6. With kerion formation, nonspecific foreign
protein therapy intramuscularly should be employed,
as well as boric acid or potassium permanganate
compresses.
7. When there is no evidence of clinical activity
as manifested by absence of scaling, pustules or
short stumps of broken-off hairs, and two weekly
successive microscopic examinations (and, if possible,
cultures) are negative, the child can be considered
cured.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1660411/pdf/calwestmed00347-0054.pdf
ETA: That last was from the 1930's, but it still supports the idea.