In some cases of suspected nail fungus there is actually no fungal infection, but only nail deformity. A 2003 source gives a figure of 50%[17] whereas a more recent source claims that fungus is present in 65 to 95 percent of cases.[18] Avoiding use of oral antifungal therapy (e.g. terbinafine) in persons without a confirmed infection is a particular concern because of the possible side effects of that treatment.[17] However, according to a 2015 study, the cost in the United States of testing with the periodic acid–Schiff stain (PAS) was about $148. Even if the cheaper KOH test is used first and the PAS test is used only if the KOH test is negative, there is a good chance that the PAS will be done (because of either a true or a false negative with the KOH test). But the terbinafine treatment only cost $10 (plus an additional $43 for liver function tests). In conclusion the authors say that terbinafine has a relatively benign adverse effect profile, with liver damage very rare, so it makes more sense cost-wise for the dermatologist to prescribe the treatment without doing the PAS test. (Another option would be to prescribe the treatment only if the potassium hydroxide test is positive, but it gives a false negative in about 20% of cases of fungal infection.) On the other hand, as of 2015 the price of topical (non-oral) treatment with efinaconazole was $2307 per nail, so testing is recommended before prescribing it.[18]

Onychomycosis – commonly known as toenail fungus – is characterized by inflammation, pain, and swelling of the toe, as well as yellowing, thickening, and crumbling of the nail itself.  Toenail fungus can be the result of abnormal pH of the skin, continuous exposure to moisture, wearing synthetic socks, compromised immune system, sweat build-up in shoes, poor foot hygiene, or weak circulation such as that caused by diabetes.
Oral antifungal therapy has a high cure rate, depending on the medication. It can take nine to 12 months to see if it has worked or not, because that is how long it takes for the nail to grow out. Even when therapy works, the fungus may come back. Currently, an oral antifungal therapy is considered the best treatment for toenail fungus because of higher cure rates and shorter treatment duration compared to topical therapy.
Keeping socks and shoes clean (using bleach in the wash) is one way to prevent fungi from taking hold and spreading. Avoiding the sharing of boots and shoes is another way to prevent transmission. Athlete's foot can be transmitted by sharing footwear with an infected person. Hand-me-downs and purchasing used shoes are other forms of shoe-sharing. Not sharing also applies to towels, because, though less common, fungi can be passed along on towels, especially damp ones.
^ Jump up to: a b American Academy of Dermatology (February 2013), "Five Things Physicians and Patients Should Question", Choosing Wisely: an initiative of the ABIM Foundation, American Academy of Dermatology, retrieved 5 December 2013. Which cites:*Roberts DT, Taylor WD, Boyle J (2003). "Guidelines for treatment of onychomycosis" (PDF). The British Journal of Dermatology. 148 (3): 402–410. doi:10.1046/j.1365-2133.2003.05242.x. PMID 12653730.

THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.

For fungus infection, there are plenty of options. Many medications are available, including miconazole (Micatin, Zeasorb powder), econazole (Spectazole), clotrimazole (Lotrimin), terbinafine (Lamisil), naftifine (Naftin), butenafine (Mentax), ciclopirox (Loprox), ketoconazole (Nizoral), efinaconazole (Jublia), luliconazole (Luzu), sertaconazole (Ertaczo), sulconazole (Exelderm), and tolnaftate (Tinactin). Ask your health care professional or pharmacist for a recommendation. It is difficult to know which of these drugs is most effective since they have not been tested against each other. Cost is probably the most significant differentiating factor, and many are available without a prescription. Treatment for athlete's foot should generally be continued for four weeks or at least one week after all of the skin symptoms have cleared.

Modern medicine addresses toenail fungus with topical treatments, oral anti-fungal medicine, and in some cases surgical removal of the nail.  Side effects of these medications may possibly include trouble breathing, swelling of the mouth or face, hives, rashes, blisters, headaches, dizziness, nausea, loss of appetite, liver damage, weight gain, fatigue, heart problems, fever, diarrhea, and more pain – all just to get rid of fungus on your toenails.
Although treatment is usually sought for cosmetic reasons, nail fungus can be serious and should be treated. For example, if it is a severe infection, it can cause permanent damage to your nails. The infection can also spread beyond your nails, especially if you are in a high risk group, such as people with diabetes or impaired immune systems. High-risk people can develop cellulitis, a skin tissue infection, if toe fungus isn't treated.[4]

THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
What you need to know about fungal infections Some fungi occur naturally in the body, and they can be helpful or harmful. An infection occurs when an invasive fungus becomes too much for the immune system to handle. We describe the most common types, including yeast infection, jock itch, and ringworm. Here, learn about risk factors and the range of treatments. Read now
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