A 2003 survey of diseases of the foot in 16 European countries found onychomycosis to be the most frequent fungal foot infection and estimates its prevalence at 27%. Prevalence was observed to increase with age. In Canada, the prevalence was estimated to be 6.48%. Onychomycosis affects approximately one-third of diabetics and is 56% more frequent in people suffering from psoriasis.

Any dermatitis may heal leaving pale skin, as may excessive use of corticosteroid creams used to treat episodes of eczema. The hypopigmentation is due to both reduced activity of melanocytes with fewer and smaller melanosomes.

The condition is most often seen in children between the ages of 3 and 16 years and is more common in males than females. However adults can also suffer from this disease.

It may occur more frequently in lighter-skinned patients, but is more apparent in those with darker complexions.

Up to a third of US school children may at some stage have this condition. Single-point prevalence studies from India have shown variable rates from 8.4%,

to 31%.

Other studies have shown prevalence rates in Brazil of 9.9%,

Egypt 13.49%,

Romania 5.1%,

Turkey 12% where higher rates were seen in those with poor socioeconomic conditions,

and just 1% in school children in Hong Kong.

Following effective treatment recurrence is common (10–50%).

Nail fungus can be painful and cause permanent damage to nails. It may lead to other serious infections if the immune system is suppressed due to medication, diabetes or other conditions. The risk is most serious for people with diabetes and with immune systems weakened by leukemia or AIDS, or medication after organ transplant. Diabetics have vascular and nerve impairment, and are at risk of cellulitis, a potentially serious bacterial infection; any relatively minor injury to feet, including a nail fungal infection, can lead to more serious complications. Infection of the bone is another rare complication.

White piedra (or tinea blanca) is a mycosis of the hair caused by several species of fungi in the genus "Trichosporon". It is characterized by soft nodules composed of yeast cells and arthroconidia that encompass hair shafts.

Tinea corporis is caused by a tiny fungus known as dermatophyte. These tiny organisms normally live on the superficial skin surface, and when the opportunity is right, they can induce a rash or infection.

The disease can also be acquired by person-to-person transfer usually via direct skin contact with an infected individual. Animal-to-human transmission is also common. Ringworm commonly occurs on pets (dogs, cats) and the fungus can be acquired while petting or grooming an animal. Ringworm can also be acquired from other animals such as horses, pigs, ferrets and cows. The fungus can also be spread by touching inanimate objects like personal care products, bed linen, combs, athletic gear, or hair brushes contaminated by an affected person.

Individuals at high risk of acquiring ringworm include those who:

- Live in crowded, humid conditions.

- Sweat excessively, as sweat can produce a humid wet environment where the pathogenic fungi can thrive. This is most common in the armpits, groin creases and skin folds of the abdomen.

- Participate in close contact sports like soccer, rugby, or wrestling.

- Wear tight, constrictive clothing with poor aeration.

- Have a weakened immune system (e.g., those infected with HIV or taking immunosuppressive drugs).

One approach involves shaving the affected areas. Another approach involves the use of antifungal medication.

Because fungi prefer warm, moist environments, preventing ringworm involves keeping skin dry and avoiding contact with infectious material. Basic prevention measures include:

- Washing hands after handling animals, soil, and plants.

- Avoiding touching characteristic lesions on other people.

- Wearing loose-fitting clothing.

- Practicing good hygiene when participating in sports that involve physical contact with other people.

Erythrasma is caused by "Corynebacterium minutissimum". This bacteria tends to thrive in mostly moist and warm environments. Great contributors are poor hygiene, obesity, hyperhidrosis, aging, diabetes mellitus, and a poor immune system. Only some of the causable factors can be looked at for prevention. Hygiene can be improved, along with avoiding moist and warm environments. The other medical factors causing the erythrasma are underlying diseases that cannot be prevented as easily, which at times, can make this condition inevitable.

The patches of pityriasis alba may last from 1 month to about one year, but commonly on the face last a year. However it is possible that the white patches may last for more than 1 year on the face.

"Corynebacterium minutissimum" is the bacteria that causes this infection, often club shaped rods when observed under a microscope following a staining procedure, which is a result of snapping division which makes them look like a picket fence. This bacteria is gram positive which means it has a very thick cell wall that cannot be easily penetrated.Electron microscopy confirms the bacterial nature of erythrasma, it shows decreased electron density in keratinized cells at the sites of proliferation. This means that the bacteria causes erythrasma by breaking down keratin Fibrils in the skin. "Corynebacterium minutissimum" consumes carbohydrates such as glucose, dextrose, sucrose, maltose, and mannitol.

Erythrasma manifests mostly in slightly webbed spaces between toes (or other body region skin folds like the thighs/groin area) in warm atmospheric regions, more prevalent in dark skinned humans. As a person ages, they are more susceptible to this infection. This bacterium is not only found in warm atmospheric regions, but also warm and sweaty parts of the human body. "Corynebacterium minutissimum" survives the best here due to the encouraged fungal growth in these regions and allows it to replicate. It is more prevalent in African Americans due to their skin pigmentation.

Advice often given includes:

- Avoid sharing clothing, sports equipment, towels, or sheets.

- Wash clothes in hot water with fungicidal soap after suspected exposure to ringworm.

- Avoid walking barefoot; instead wear appropriate protective shoes in locker rooms and sandals at the beach.

- Avoid touching pets with bald spots, as they are often carriers of the fungus.

Opportunistic infections (infections that are caused by a diminished immune system) are frequent. Fungus from an athlete's foot infection can spread to the groin through clothing. Tight, restrictive clothing, such as jockstraps, traps heat and moisture, providing an ideal environment for the fungus.

The type of fungus involved is usually "Trichophyton rubrum". Some other contributing fungi are "Candida albicans", "Trichophyton mentagrophytes" and "Epidermophyton floccosum".

Tinea capitis caused by species of "Microsporum" and "Trichophyton" is a contagious disease that is endemic in many countries. Affecting primarily pre-pubertal children between 6 and 10 years, it is more common in males than females; rarely does the disease persist past age sixteen. Because spread is thought to occur through direct contact with afflicted individuals, large outbreaks have been known to occur in schools and other places where children are in close quarters; however, indirect spread through contamination with infected objects ("fomites") may also be a factor in the spread of infection. In the USA, tinea capitis is thought to occur in 3-8% of the pediatric population; up to one-third of households with contact with an infected person may harbor the disease without showing any symptoms.

The fungal species responsible for causing tinea capitis vary according to the geographical region, and may also change over time. For example, "Microsporum audouinii" was the predominant etiological agent in North America and Europe until the 1950s, but now "Trichophyton tonsurans" is more common in the USA, and becoming more common in Europe and the United Kingdom. This shift is thought to be due to the widespread use of griseofulvin, which is more effective against "M. audounii" than "T. tonsurans"; also, changes in immigration patterns and increases in international travel have likely spread "T. tonsurans" to new areas. Another fungal species that has increased in prevalence is "Trichophyton violaceum", especially in urban populations of the United Kingdom and Europe.

Besides being exposed to any of the modes of transmission presented above, there are additional risk factors that increase one's chance of contracting athlete's foot. Persons who have had athlete's foot before are more likely to become infected than those who have not. Adults are more likely to catch athlete's foot than children. Men have a higher chance of getting athlete's foot than women. People with diabetes or weakened immune systems are more susceptible to the disease. HIV/AIDS hampers the immune system and increases the risk of acquiring athlete's foot. Hyperhidrosis (abnormally increased sweating) increases the risk of infection and makes treatment more difficult.

This skin disease commonly affects adolescents and young adults, especially in warm and humid climates. The yeast is thought to feed on skin oils (lipids), as well as dead skin cells. Infections are more common in people who have seborrheic dermatitis, dandruff, and hyperhidrosis.

Favid (of "favus" Latin for "honeycomb" or tinea favosa) is a disease usually affecting the scalp, but occurring occasionally on any part of the skin, and even at times on mucous membranes.

The word “Favid” is more used than French word “favus”, which is close to the Latin etymology.

According to the National Health Service, "Athlete’s foot is very contagious and can be spread through direct and indirect contact." The disease may spread to others directly when they touch the infection. People can contract the disease indirectly by coming into contact with contaminated items (clothes, towels, etc.) or surfaces (such as bathroom, shower, or locker room floors). The fungi that cause athlete's foot can easily spread to one's environment. Fungi rub off of fingers and bare feet, but also travel on the dead skin cells that continually fall off the body. Athlete's foot fungi and infested skin particles and flakes may spread to socks, shoes, clothes, to other people, pets (via petting), bed sheets, bathtubs, showers, sinks, counters, towels, rugs, floors, and carpets.

When the fungus has spread to pets, it can subsequently spread to the hands and fingers of people who pet them. If a pet frequently gnaws upon itself, it might not be fleas it is reacting to, it may be the insatiable itch of tinea.

One way to contract athlete's foot is to get a fungal infection somewhere else on the body first. The fungi causing athlete's foot may spread from other areas of the body to the feet, usually by touching or scratching the affected area, thereby getting the fungus on the fingers, and then touching or scratching the feet. While the fungus remains the same, the name of the condition changes based on where on the body the infection is located. For example, the infection is known as tinea corporis ("ringworm") when the torso or limbs are affected or tinea cruris (jock itch or dhobi itch) when the groin is affected. Clothes (or shoes), body heat, and sweat can keep the skin warm and moist, just the environment the fungus needs to thrive.

Tinea imbricata (also known as "Tokelau" and in parts of Indonesia as “Kaskado”) is a superficial fungal infection of the skin limited to southwest Polynesia, Melanesia, Southeast Asia, India, and Central America.The skin lesions are often itchy, and mainly in the torso and limbs. The name is derived from the Latin for "tiled" (imbricata) since the lesions are often lamellar. It is often treated with griseofulvin or terbinafine.

It is associated with "Trichophyton concentricum".

This infection is caused by the fungus formerly classified as "Exophiala werneckii", but more recently classified as "Hortaea werneckii". The causative organism has also been described as "Phaeoannellomyces werneckii".

The exact cause of Majocchi's granuloma is not well established however a dysfunctinoal immune system may be a causative factor. The first form of MG, the superficial perifollicular form occurs predominately on the legs of otherwise healthy young women who repeatedly shave their legs and develop hair follicle occlusions that directly or indirectly disrupt the follicle and allow for passive introduction of the organism into the dermis. Hence, the physical barrier of the skin is important because it prevents the penetration of microorganisms. Physical factors that play a major role in inhibiting dermal invasion include the interaction among keratin production, the rate of epidermal turnover, the degree of hydration and lipid composition of the stratum corneum, CO levels, and the presence or absence of hair. Keratin and/or necrotic material can also be introduced into the dermis with an infectious organism to further enhance the problem. In immunocompromised individuals, the use of topical corticosteroids may lead to a dermatophyte infection due to local immunosuppression.

It is very rare and estimated to affect 1 in 100,000 per year. Because of its rarity the documentation, cases and information are sparse and not a huge amount is known for certain, meaning that EAC could actually be a set of many un-classified skin lesions. It is known to occur at all ages and all genders equally. Some articles state that women are more likely to be affected than men.

Tinea cruris is similar to, but different from Candidal intertrigo, which is an infection of the skin by "Candida albicans". The latter is more specifically located between intertriginous folds of adjacent skin, which can be present in the groin or scrotum, and be indistinguishable from fungal infections caused by "tinea". However, candidal infections tend to both appear and with treatment disappear more quickly. It may also affect the scrotum.

Tinea nigra (also known as "superficial phaeohyphomycosis," and "Tinea nigra palmaris et plantaris") is a superficial fungal infection that causes dark brown to black painless patches on the palms of the hands and the soles of the feet.

A number of different species of fungi are involved in dermatophytosis. Dermatophytes of the genera "Trichophyton" and "Microsporum" are the most common causative agents. These fungi attack various parts of the body and lead to the conditions listed below. The Latin names are for the conditions (disease patterns), not the agents that cause them. The disease patterns below identify the type of fungus that causes them only in the cases listed:

- Dermatophytosis

- Tinea pedis (athlete's foot) – fungal infection of the feet

- Tinea unguium – fungal infection of the fingernails and toenails, and the nail bed

- Tinea corporis – fungal infection of the arms, legs, and trunk

- Tinea cruris (jock itch) – fungal infection of the groin area

- Tinea manuum – fungal infection of the hands and palm area

- Tinea capitis – fungal infection of the scalp and hair

- Tinea barbae – fungal infestation of facial hair

- Tinea faciei (face fungus) – fungal infection of the face

- Other superficial mycoses (not classic ringworm, since not caused by dermatophytes)

- Tinea versicolor – caused by "Malassezia furfur"

- Tinea nigra – caused by "Hortaea werneckii"

The uncomplicated appearance is that of a number of yellowish, circular, cup-shaped crusts (scutula) grouped in patches like a piece of honeycomb, each about the size of a split pea, with a hair projecting in the center. These increase in size and become crusted over, so that the characteristic lesion can only be seen round the edge of the scab. A mousy odour is often present. Growth continues to take place for several months, when scab and scutulum come away, leaving a shining bare patch destitute of hair. The disease is essentially chronic, lasting from ten to twenty years. It is caused by the growth of a fungus, and pathologically is the reaction of the tissues to the growth.

The fungus was named after a microscopic structure termed "achorion" (a term not used in modern science), seen in scrapings of infected skin, which consists of slender, mycelial threads matted together, bearing oval, nucleated fungal substrate-arthroconidia either free or jointed. This structure is currently called "scutula." The fungus itself is now called "Trichophyton schoenleinii".

During initial infection, the fungal spores would appear to enter through the unbroken cutaneous surface, and to germinate mostly in and around the hair follicle and sometimes in the shaft of the hair.