Superficial scrapes of skin examined underneath a microscope may reveal the presence of a fungus. This is done by utilizing a diagnostic method called KOH Test, wherein the skin scrapings are placed on a slide and immersed on a dropful of potassium hydroxide solution to dissolve the keratin on the skin scrappings thus leaving fungal elements such as hyphae, septate or yeast cells viewable. If the skin scrapings are negative and a fungus is still suspected, the scrapings are sent for culture. Because the fungus grows slowly, the culture results do take several days to become positive.

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.

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.

no approved human vaccine exist against "Dermatophytosis". For horses, dogs and cats there is available an approved inactivated vaccine called "Insol Dermatophyton" (Boehringer Ingelheim) which provides time-limited protection against several trichophyton and microsporum fungal strains.

Dempster-Shafer Theory is used for detecting skin infection and displaying the result of the detection process.

Tinea capitis may be difficult to distinguish from other skin diseases that cause scaling, such as psoriasis and seborrhoeic dermatitis; the basis for the diagnosis is positive microscopic examination and microbial culture of epilated hairs. Wood's lamp (blacklight) examination will reveal bright green to yellow-green fluorescence of hairs infected by "M. canis", "M. audouinii", "M. rivalieri", and "M. ferrugineum" and a dull green or blue-white color of hairs infected by "T. schoenleinii". Individuals with "M. canis" infection trichoscopy will show characteristic small comma hairs. Histopathology of scalp biopsy shows fungi sparsely distributed in the stratum corneum and hyphae extending down the hair follicle, placed on the surface of the hair shaft. These findings are occasionally associated with inflammatory tissue reaction in the local tissue.

The treatment of choice by dermatologists is a safe and inexpensive oral medication, griseofulvin, a secondary metabolite of the fungus "Penicillium griseofulvin". This compound is "fungistatic" (inhibiting the growth or reproduction of fungi) and works by affecting the microtubular system of fungi, interfering with the mitotic spindle and cytoplasmic microtubules. The recommended pediatric dosage is 10 mg/kg/day for 6–8 weeks, although this may be increased to 20 mg/kg/d for those infected by "T. tonsurans", or those who fail to respond to the initial 6 weeks of treatment. Unlike other fungal skin infections that may be treated with topical therapies like creams applied directly to the afflicted area, griseofulvin must be taken orally to be effective; this allows the drug to penetrate the hair shaft where the fungus lives. The effective therapy rate of this treatment is generally high, in the range of 88–100%.

Other oral antifungal treatments for tinea capitis also frequently reported in the literature include terbinafine, itraconazole, and fluconazole; these drugs have the advantage of shorter treatment durations than griseofulvin. However, concern has been raised about the possibility of rare side effects like liver toxicity or interactions with other drugs; furthermore, the newer drug treatments tend to be more expensive than griseofulvin.

On September 28, 2007, the U.S. Food and Drug Administration stated that Lamisil (Terbinafine hydrochloride, by Novartis AG) is a new treatment approved for use by children aged 4 years and older. The antifungal can be sprinkled on a child's food to treat the infection. Lamisil carries hepatotoxic risk, and can cause a metallic taste in the mouth.

A dermatomycosis is a skin disease caused by a fungus. This excludes dermatophytosis.

Examples of dermatomycoses are tinea and cutaneous candidiasis.

Virus-related cutaneous conditions are caused by two main groups of viruses–DNA and RNA types–both of which are obligatory intracellular parasites.

Sycosis vulgaris (also known as "Barber's itch," and "Sycosis barbae") is a cutaneous condition characterized by a chronic infection of the chin or bearded region. The irritation is caused by a deep infection of hair follicles, often by species of "Staphylococcus" or "Propionibacterium" bacteria. Asymptomatic or painful and tender erythematous papules and pustules may form around coarse hair in the beard (sycosis barbae) or the back of the neck (sycosis nuchae).

A skin biopsy can be performed to test for EAC; tests should be performed to rule out other possible diseases such as: pityriasis rosea, tinea corporis, psoriasis, nummular eczema, atopic dermatitis, drug reaction, erythema migrans and other rashes.

Fungal folliculitis (also known as Majocchi granuloma) is a skin condition characterized by a deep, pustular type of tinea circinata resembling a carbuncle or kerion.

Gram-negative toe web infection is a cutaneous condition that often begins with dermatophytosis.

Lupoid sycosis is a cutaneous condition that is characterized by a scarring form of deep folliculitis, typically affecting the beard area.

With no particular affinity to any particular ethnic group, seen in all age groups and equally amongst males and females, the precise prevalence is not known.

No treatment is usually needed as they usually go away anywhere from months to years. The lesions may last from anywhere between 4 weeks to 34 years with an average duration of 11 months. If caused by an underlying disease or malignancy, then treating and removing the disease or malignancy will stop the lesions. It usually doesn't require treatment, but topical corticosteroids may be helpful in reducing redness, swelling and itchiness.

Some supported and not supported methods of having an effect on EAC include:

- Photosensitive so it can be moved/reduced with appropriate sunlight.

- Vitamin D

- Immune system - hence it will increase in size/number when the immune system is low or overloaded.

- Hormone Drugs

- Disulone

- Stress reduction

- Topical calcipotriol - a topical vitamin D derivative has been known to be beneficial

Other rashes that occur in a widespread distribution can look like an id reaction. These include atopic dermatitis, contact dermatitis, dyshidrosis, photodermatitis, scabies and drug eruptions.

Other conditions that may mimic cellulitis include deep vein thrombosis, which can be diagnosed with a compression leg ultrasound, and stasis dermatitis, which is inflammation of the skin from poor blood flow. Signs of a more severe infection such as necrotizing fasciitis or gas gangrene that would require prompt surgical intervention include purple bullae, skin sloughing, subcutaneous edema, and systemic toxicity. Misdiagnosis can occur in up to 30% of people with suspected lower-extremity cellulitis, leading to 50,000 to 130,000 unnecessary hospitalization and $195 to $515 million in avoidable healthcare spending annually in the United States.

Associated musculoskeletal findings are sometimes reported. When it occurs with acne conglobata, hidradenitis suppurativa, and pilonidal cysts, the syndrome is referred to as the follicular occlusion triad or tetrad.

Lyme disease can be misdiagnosed as staphylococcal- or streptococcal-induced cellulitis. Because the characteristic bullseye rash does not always appear in people infected with Lyme disease, the similar set of symptoms may be misdiagnosed as cellulitis. Standard treatments for cellulitis are not sufficient for curing Lyme disease. The only way to rule out Lyme disease is with a blood test, which is recommended during warm months in areas where the disease is endemic.

Gram-negative folliculitis occurs in patients who have had moderately inflammatory acne for long periods and have been treated with long-term antibiotics, mainly tetracyclines, a disease in which cultures of lesions usually reveals a species of "Klebsiella", "Escherichia coli", "Enterobacter", or, from the deep cystic lesions, "Proteus".

In those who have previously had cellulitis, the use of antibiotics may help prevent future episodes. This is recommended by CREST for those who have had more than two episodes.

Gram-negative toe web infection is a relatively common infection. It is commonly found on people who are engaged in athletic activities while wearing closed-toe or tight fitting shoes. It grows in a moist environment. Gram-negative is mixed bacterial infection with the following organisms:

- Moraxella

- Alcaligenes

- Acinetobacter

- Pseudomonas

- Proteus

- Erwinia

This mixing of infection and organisms may also cause a mild secondary infection of tinea pedis.

Subcutaneous granuloma annulare (also known as "Deep granuloma annulare," and "Pseudorheumatoid nodule") is a skin condition of unknown cause, most commonly affecting children, with girls affected twice as commonly as boys, characterized by skin lesions most often on the lower legs.

Hospital furunculosis is a cutaneous condition that can be epidemic in the hospital setting, characterized histopathologically by a deep abscess with both lymphocytes and neutrophils.

There is no cure for this condition. Treatment is generally lifelong and takes the form of bathing and soaking in mineral oils and washing with antibiotic shampoos to try to alleviate symptoms and slow the condition's progression. Antiseptic and antibiotic shampoos (chlorhexidine or benzoyl peroxide) are used to manage further secondary bacterial infection. For some breeds, cyclosporine or corticosteroids and immunosuppressant drugs may be effective, and it is postulated, through some studies, that large doses of vitamin A given orally may result in some improvement.

It has been suggested that the more aggressively one applies the topical methods of treatment, the less aggressively one needs to employ the immunosuppressant therapy. The suggestion is that this phenomenon may be due to a feedback whereby secondary infection, when not aggressively treated with topical therapy, increases and contributes to further sebaceous gland inflammation.

This forms a major and critical part in the disease treatment and the shampoo treatment can need to be applied as often as 3 to 4 times per week. An antiseborrheic shampoo removes the scale blocking theolr follicles. The mineral oil soak, whereby the oil remains on the affected animal for at least 2 hours, is needed to replace epidemal lipids as well as to restore normal epidermal barrier function. The oil is then removed through the process of many baths. This oil treatment needs to be repeated at least once a week for 4 to 7 weeks until new hair growth is observed. Once new hair growth is observed, topical treatment can be decreased to every 2 to 4 weeks.