Your physician may perform a simple test called a potassium hydroxide (KOH) preparation for microscopic fungal examination in the office or laboratory. This test can be used to confirm the presence of a fungal infection. This test is performed by using a microscope to examine small flakes of skin from the rash. Many dermatologists perform this test in their office with results available within minutes. Rarely, a small piece of skin may be removed and sent for biopsy or fungal culture to help confirm the diagnosis.
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
Athlete's foot was first medically described in 1908.[9] Globally, athlete's foot affects about 15% of the population.[2] Males are more often affected than females.[4] It occurs most frequently in older children or younger adults.[4] Historically it is believed to have been a rare condition, that became more frequent in the 1900s due to the greater use of shoes, health clubs, war, and travel.[10]
All high heels boost the risk of an ankle sprain. The most common problem is a lateral sprain, which happens when you roll onto the outside of the foot. This stretches the ankle ligaments beyond their normal length. A severe sprain may tear the ligaments. A sprained ankle should be immobilized and may need physical therapy to heal properly. The risk of developing osteoarthritis rises with a severe sprain or fracture of the ankle.
Readily available over-the-counter treatments work well for most nail-bed infections, especially early cases. An advanced toenail fungus infection may require a podiatrist’s intervention. To counteract a serious infection, medical professionals may utilize prescription topical medications, oral medications, and even laser therapy.  Some cases best respond to combination therapy.
Trichophyton rubrum is the most common dermatophyte involved in onychomycosis. Other dermatophytes that may be involved are T. interdigitale, Epidermophyton floccosum, T. violaceum, Microsporum gypseum, T. tonsurans, and T. soudanense. A common outdated name that may still be reported by medical laboratories is Trichophyton mentagrophytes for T. interdigitale. The name T. mentagrophytes is now restricted to the agent of favus skin infection of the mouse; though this fungus may be transmitted from mice and their danders to humans, it generally infects skin and not nails.

Nail-bed fungus is also called onychomycosis. It can affect anyone regardless of age, gender and hygiene and is spread by direct contact with skin or with infected surfaces. Common places you may be exposed to fungus are at nail salons, as well as showers at hotels, pools, nail salons, and gyms where you go barefoot. Housemates and family members with a fungal infection may also spread their condition.
Yeast onychomycosis: This type is caused by a yeast called Candida and not by the Trichophyton fungus named above. It is more common in fingernails and is a common cause of fungal fingernails. Patients may have associated paronychia (infection of the cuticle). Candida can cause yellow, brown, white, or thickened nails. Some people who have this infection also have yeast in their mouth or have a chronic paronychia (see above) that is also infected with yeast.
Athlete's foot is divided into four categories or presentations: chronic interdigital athlete's foot, plantar (chronic scaly) athlete's foot (aka "moccasin foot"), acute ulcerative tinea pedis,[11] and vesiculobullous athlete's foot.[2][12][13] "Interdigital" means between the toes. "Plantar" here refers to the sole of the foot. The ulcerative condition includes macerated lesions with scaly borders.[11] Maceration is the softening and breaking down of skin due to extensive exposure to moisture. A vesiculobullous disease is a type of mucocutaneous disease characterized by vesicles and bullae (blisters). Both vesicles and bullae are fluid-filled lesions, and they are distinguished by size (vesicles being less than 5–10 mm and bulla being larger than 5–10 mm, depending upon what definition is used).
Ultra-high heels force the feet into a position that puts stress on the ball of the foot. At this critical joint, the long metatarsal bones meet the pea-shaped sesamoid bones, and the toe bones (phalanges). Too much pressure can inflame these bones or the nerves that surround them. Chronic stress to the foot bones can even lead to hairline fractures.
Readily available over-the-counter treatments work well for most nail-bed infections, especially early cases. An advanced toenail fungus infection may require a podiatrist’s intervention. To counteract a serious infection, medical professionals may utilize prescription topical medications, oral medications, and even laser therapy.  Some cases best respond to combination therapy.
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]
Prescription oral antifungals such as terbinafine (Lamisil) or fluconazole (Diflucan) are traditionally used to treat toenail fungus. These treatments are often effective, but they may cause serious side effects ranging from upset stomach and dizziness to severe skin problems and jaundice. This may be why many people try home remedies instead. Here are 10 of these popular at-home treatments.
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