My dermatologist diagnosed me with a yeast infection of my fingernails. She does not want me to use any oral medications, due to the side effects. She also said there is a topical medication, but I have a young child, and she does not want me to use the medication while handling my child. So, what can I do? Are there any natural remedies I can use to treat it? What happens if I don't treat it?

M.

There are two main causes of fungal nail infections: Candida albicans (the yeast that commonly causes oral and vaginal yeast infections) and the dermatophyte molds ringworm and athlete's foot.) Some people use the terms yeast and fungus interchangeably. However, there is a big difference between yeast and dermatophyte nail infections.

Yeasts more commonly cause paronychia, which is a painful infection adjacent to the nail. Candida can also cause onychomycosis, a chronic, usually painless infection that results in thickening and discoloration of the nail. Nail infections caused by Candida usually affect the fingers rather than the toes and occur most commonly in people who frequently immerse their hands in water.

However, most nail infections are caused by dermatophytes. Although dermatophyte toenail infections are extremely common, fingernail infections occur as well. These range from a superficial whitening of the ends of the nails to deep involvement of the entire nail, which takes on a brown or black discoloration. Usually, there is associated infection of the nearby skin, in the form of athlete's foot or infection of the fingers themselves. Since nail infections are generally painless, the main complaint of people with onychomycosis is cosmetic.

If you have Candida (true yeast) paronychia -- that is, a Candida infection adjacent to the nail -- then the treatment involves applying a topical cream and avoiding immersing your hands in water. I am not sure why your physician is concerned about you using a topical agent and handling your child, because there are many safe antifungal creams that should not harm your kid. In fact, these same drugs are used to treat fungal skin infections in babies. If you have a infection of the nail itself due to Candida or a dermatophyte, oral therapy is the best choice. Occasionally, very superficial nail infections can be cured with a topical agent, but as a rule, topical therapy fails in such cases. There are two choices for oral therapy: terbinafine (Lamisil) and itraconazole (Sporanox.) Itraconazole can be used for both Candida and the dermatophytes, but terbinafine can only be used for the dermatophytes.

It is true that these drugs can sometimes have side effects, but most people tolerate them well. The main concern for both of these drugs is liver toxicity, but serious damage to the liver is actually quite rare. For fingernail infections, usually only six weeks of treatment is necessary, while 12 weeks or longer is recommended for toenail infections. If you have a true nail infection, I would recommend one of these two drugs. The main reason that some of my patients do not try oral therapy is the cost, as most insurance carriers do not cover it.

I am not aware of any natural remedies that are acceptable treatments for true fungal nail infection. Topical application of boric acid may treat some superficial yeast infections, but I do not recommend it. I personally do not think that just because something is "natural," it is safer to use. Amphotericin B, for example, a natural substance made by certain bacteria, is the treatment of choice for most serious, invasive fungal infections. But it is quite toxic, causing at least some degree of kidney damage in most patients. Poison mushrooms and hemlock are also natural, yet obviously toxic. You should research so-called natural remedies just as much as conventional medicines before you decide if they are safe.