Dear Christopher Cat
I have two 18-year-old cats who have repeated episodes of ringworm.
The hair loss is usually only on their heads, so recently I put a little tolnaftate powder on the backs of their necks, as suggested on the Internet.
One cat was fine, but the other got very sick. Is tolnaftate safe for cats?
It is generally safe, but it’s not very effective in cat ringworm.
Ringworm is caused by microscopic fungal spores that invade pets’ hair follicles. The ringworm fungus irritates the follicles so much that the hair falls out.
While tolnaftate (Tinactin) athlete’s foot powder is good for treating fungal infections on human skin, it isn’t very effective in animal ringworm because it doesn’t penetrate hair follicles well.
Instead, try a topical antifungal cream prescribed by your veterinarian for your cats’ heads.
If that’s not effective, consider shampoos and dips, which are most effective on long-haired cats if they are shaved. I’m glad I never had ringworm, because I’d be so much less handsome without my long, thick hair.
If you feel your cats are too frail to be dipped, your veterinarian might prescribe an oral medication such as itraconazole.
Some veterinarians also recommend lufenuron (sold as Program for flea control) as adjunctive therapy because it inhibits the formation of chitin, a component of the cell wall of the ringworm fungus.
Because fungal spores remain infective for a year or more, it’s essential to clean your home well to prevent recurrences of ringworm. Discard furnace filters, and vacuum or wash everything else.
Ringworm can be transmitted to humans, particularly children and people with compromised immune systems, so call your doctor if you see any changes in your skin.