Athlete's foot is caused by a number of different fungi.[3] These include species of Trichophyton, Epidermophyton, and Microsporum.[4] The condition is typically acquired by coming into contact with infected skin, or fungus in the environment.[3] Common places where the fungi can survive are around swimming pools and in locker rooms.[8] They may also be spread from other animals.[5] Usually diagnosis is made based on signs and symptoms; however, it can be confirmed either by culture or seeing hyphae using a microscope.[4]
You might cringe at the thought of having a fungal or yeast infection. The concept might feel icky. The reality, however, is that many types of fungi live on the skin all the time, even though you can't see them. Most of the time, these fungi don't cause any problems, but sometimes a fungus will change and cause an infection. These are some of the more common fungal and yeast infections that people experience.
Athlete's foot, known medically as tinea pedis, is a common skin infection of the feet caused by fungus.[2] Signs and symptoms often include itching, scaling, cracking and redness.[3] In rare cases the skin may blister.[6] Athlete's foot fungus may infect any part of the foot, but most often grows between the toes.[3] The next most common area is the bottom of the foot.[6] The same fungus may also affect the nails or the hands.[4] It is a member of the group of diseases known as tinea.[7]
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 A common outdated name that may still be reported by medical laboratories is Trichophyton mentagrophytes for T. interdigitale.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.
Fungal infection occurs when the organism invades through an opening in the nail, meaning fungi will usually attack nails that are already damaged. After infection occurs, the growth of the fungi leads to mild inflammation, which causes the nail to thicken and the nail plate to detach from the nail bed. The space underneath the nail can then serve as a reservoir for bacteria and moulds, which can cause the nail to become discoloured.
Topical antifungal agents can be used but are often ineffective. Oral terbinafine is considered to be the first-line treatment for confirmed onychomycosis; the treatment course is generally 6 weeks for fingernails and 12 weeks for toenails.9 Azoles can also be used. Surgical debridement or removal of the affected nail is also a consideration for cases that are resistant to antifungals, and laser treatments for onychomycosis appear to be a promising area for future study.10

There are many topical antifungal drugs useful in the treatment of athlete's foot including: miconazole nitrate, clotrimazole, tolnaftate (a synthetic thiocarbamate), terbinafine hydrochloride,[17] butenafine hydrochloride and undecylenic acid. The fungal infection may be treated with topical antifungal agents, which can take the form of a spray, powder, cream, or gel. Topical application of an antifungal cream such as terbinafine once daily for one week or butenafine once daily for two weeks is effective in most cases of athlete's foot and is more effective than application of miconazole or clotrimazole.[23] Plantar-type athlete's foot is more resistant to topical treatments due to the presence of thickened hyperkeratotic skin on the sole of the foot.[13] Keratolytic and humectant medications such as urea, salicyclic acid (Whitfield's ointment), and lactic acid are useful adjunct medications and improve penetration of antifungal agents into the thickened skin.[13] Topical glucocorticoids are sometimes prescribed to alleviate inflammation and itching associated with the infection.[13]
Try using oil of oregano along with another essential oil called melaleuca, which is also known as tea tree oil. The uses of tea tree oil will astound you, including its ability to act as a natural antifungal agent. Use these two oils topically on your toenail fungus daily. I recommend three drops of oil of oregano and two drops of melaleuca applied directly on the toenail, four times a day, ideally.
Dermatophytes — fungus that grows on the skin, hair and nails but don’t penetrate tissues of the body. Athlete’s foot or Trichophyton rubrum is the most common dermatophyte and can actually infect the toenails. Infection can also begin by touching objects that have dermatophytes on them, such as nail clippers, nail files, socks, shoes, shower floors, etc. Dermatophytes are the cause of most fungal toenail infections.
Topical antifungal agents can be used but are often ineffective. Oral terbinafine is considered to be the first-line treatment for confirmed onychomycosis; the treatment course is generally 6 weeks for fingernails and 12 weeks for toenails.9 Azoles can also be used. Surgical debridement or removal of the affected nail is also a consideration for cases that are resistant to antifungals, and laser treatments for onychomycosis appear to be a promising area for future study.10
Red or black nails due to a hematoma, or blood under the nail, usually occur from trauma (like whacking yourself on the thumb with a hammer). The discolored area will grow out with the nail and be trimmed off as you trim your nails. If you have a black spot under your nail that was not caused by trauma, you may want to see a dermatologist or a podiatrist if it involves a toenail to make sure it is not melanoma (a type of skin cancer associated with pigmented cells). A simple biopsy can rule out malignancy (cancer).

One way to definitively get rid of toenail fungus is by surgery. Surgical treatment of onychomycosis involves nail removal. However, this often only provides temporary relief, and recurrence is common unless additional antifungal medication (oral or topical) is simultaneously used. However, surgical removal may be warranted when the affected nail is associated with other factors such as trauma and or infection.
Tea tree oil, also called melaleuca, is an essential oil with antifungal and antiseptic abilities. According to the National Center for Complementary and Integrative Health, some small-scale clinical studies showed that tea tree oil might be effective against toenail fungus. To use, paint the tea tree oil directly onto the affected nail twice daily with a cotton swab. Find therapeutic-grade tea tree oil on Amazon.
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.
Wei, Y.-X., Xu, X.-Y., Xu, & Song, X. (2017). A review of antifungal natural products against the pathogenic fungi causing athletes' foot disease. Current Organic Chemistry, 21, 1–13. Retrieved from https://www.researchgate.net/profile/Xun_Song/publication/319128408_A_Review_of_Antifungal_Natural_Products_Against_the_Pathogenic_Fungi_Causing_Athletes'_Foot_Disease/links/59931c65458515c0ce61efa1/A-Review-of-Antifungal-Natural-Products-Against-the-Pathogenic-Fungi-Causing-Athletes-Foot-Disease.pdf
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