There are differential diagnosis' for erythrasma which includes psoriasis, candidasis, dermaphytosis, and interigo. The diagnosis can be made on the clinical picture alone. However, a simple side-room investigation with a Wood's lamp is additionally useful in diagnosing erythrasma. The ultraviolet light of a Wood's lamp causes the organism to fluoresce a characteristic coral red color, differentiating it from other skin conditions such as tinea versicolor, which may fluoresce a copper-orange color. Another route to differentiate erythrasma would be through bacterial and mycology related cultures to compare/contrast normal results to these findings. These are both non-invasive routes.

Erythrasma is often mistakenly diagnosed as dermatophytic infection which is a fungal infection and not a bacterial infection. The difference here is that fungi are multicellular and eukaryotes while bacteria are single celled prokaryotes. This is vital to differentiate because of the way they reproduce will indicate how the infection will spread throughout the human body.

Recent research for Erythrasma is mainly focused on the treatments and which methods work best to treat the patient depending on the severity of the condition. In a 2016 study performed by Prathyusha Prabhakar and H. Hema, they looked into comparing 2% clotrimazole cream and 2% Fusidic cream in treating erythrasma. This was a one year long hospital based study in South India that resulted in stating that the groin was the most common site for the symptoms of itching and discloloration being predominant and also mostly in men. The general conclusion made was that topical 2% fusidic acid cream was found to be more effective than 2% clotrimazole cream in patients with erythrasma. The topical 2% clotrimazole cream was more effective only when an associated fungal infection was present.

Another study performed in early 2017 by Tanya Grewal and Philip Cohen looked directly at mupirocin 2% ointment monotherapy. This study was done with nine males who showed a presence of erythrasma at bilateral inguinal folds, medial thighs, and axillae. After initial diagnosis by Wood lamp's examination to confirm the diagnosis, the antibiotic cream was distributed. Mupirocin is a topical antibiotic that is usually used to treat Streptococcus and Staphylococcus infections. After 2-4 weeks of use, the erythrasma seemed to clear up. They were able to conclude that the application of 2% Mupirocin ointment monotherapy twice a day, everyday is a great consideration for a first line of treatment for erythrasma.

A study done in 2011 by M. Inci and G. Serarslan revolved around detecting the frequency and risk factors of interdigital erythrasma in patients who were possibly diagnosed with Tinea pedis. The study was done with 122 people who had a confirmed diagnoses of erythrasma through the Wood's lamp method. The results showed that erythrasma was more prevalent in males who were over the age of 40 years. Their conclusions were that erythrasma is a common condition and can also easily mimic other infections such as tinea pedis and that gram staining is a better tool to differentiate the bacteria and it's mechanism than the Wood's lamp method.

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.

Sunscreen and protective clothing should also be used during the hottest part of the day to avoid blisters from sunburn. Avoiding sunlight during midday is the best way to avoid blisters from sunburn. Protective gloves should be worn when handling detergents, cleaning products, solvents and other chemicals.

Friction blisters, caused by rubbing against the skin, can be prevented by reducing the friction to a level where blisters will not form. This can be accomplished in a variety of ways.

Blisters on the feet can be prevented by wearing comfortable, well-fitting shoes and clean socks. Inherently ill-fitting or stiffer shoes, such as high heels and dress shoes, present a larger risk of blistering. Blisters are more likely to develop on skin that is moist, so socks that manage moisture or frequent sock changes will aid those with particularly sweaty feet. While exercising or playing sports, special sports socks can help keep feet drier and reduce the chance of blisters. Before going for a long walk, it is also important to ensure that shoes or hiking boots have been properly broken in.

Even before a "hot" or irritated area on the foot is felt, taping a protective layer of padding or a friction-reducing interface between the affected area and the footwear can prevent the formation of a blister. Bandages, moleskin and tapes generally must be applied to the foot daily, and most have a very high coefficient of friction (COF), but a friction-management patch applied to the shoe will remain in place much longer, throughout many changes of socks and insoles. This type of intervention may be used with footwear that is worn daily, with specialty shoes and boots like hockey skates, ice skates, inline skates, ski boots and cleats, or even with orthotic braces and splints. For periods of sustained use such as hiking and trail running, especially where water ingress or moisture build up in the shoe or boot can occur, moisture wicking liner socks can provide the required friction protection.

To avoid friction blisters on the hands, gloves should be worn when using tools such as a shovel or pickaxe, doing manual work such as gardening, or using sports equipment like golf clubs or baseball bats. Oars used for competitive rowing are known for causing frequent blisters on the hands of oarsmen. Weightlifters are also prone to blisters as are gymnasts from the friction developed by the rubbing against the bars. To further reduce the occurrence one can tape the hands, and there are also a number of products on the market that claim to reduce the occurrence of blisters. These are all intended to be worn as a liner underneath a glove. The majority of these offerings simply add padding and create a layer that reduces the coefficient of friction between the skin and the glove.

A lubricant, typically talcum powder, can be used to reduce friction between skin and apparel in the short term. People put talcum powder inside gloves or shoes for this purpose, although this type of lubricant will increase the friction in the long term, as it absorbs moisture. Increased friction makes blisters more likely.

To exclude other differential diagnoses, a skin biopsy may be taken. Imaging studies can be used in order to detect any underlying bony abnormalities that cause abnormal pressure on the overlying skin. For this purpose, a plain radiograph usually suffices, but, occasionally, CT scanning is used.

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.

Intertrigo can be diagnosed clinically by a medical professional after taking a thorough history and performing a detailed physical examination. Many other skin conditions can mimic intertrigo's appearance including erythrasmascabies, pyoderma, atopic dermatitis, candidiasis, and seborrheic dermatitis, and fungal infections of the superficial skin caused by "Tinea versicolor" or "Tinea corporis".

Diagnosis is most commonly done with the identification of bacteria in the lesions by a microscope observation. Ticks, biting flies, and contact with other infected animals also causes the spread of rainscald. A scab will be taken from the affected animal and stained so that the bacteria are visible under a microscope inspection. A positive diagnosis of rainscald can be confirmed if filamentous bacteria are observed with as well as chains of small, spherical bacteria. If a diagnosis cannot be confirmed with a microscope, blood agar cultures can be grown to confirm the presence of "D. congolensis". The resulting colonies have filaments and are yellow in colour.

The diagnosis of SSSS is made clinically. This is sometimes confirmed by isolation of "S. aureus" from blood, mucous membranes, or skin biopsy; however, these are often negative. Skin biopsy may show separation of the superficial layer of the epidermis (intraepidermal separation), differentiating SSSS from TEN, wherein the separation occurs at the dermo-epidermal junction (subepidermal separation). SSSS may be difficult to distinguish from toxic epidermal necrolysis and pustular psoriasis.

When no pus is present, warm soaks for acute paronychia is reasonable, even though there is a lack of evidence to support its use. Antibiotics such as clindamycin or cephalexin are also often used, the first being more effective in areas where MRSA is common. If there are signs of an abscess (the presence of pus) drainage is recommended.

Chronic paronychia is treated by avoiding whatever is causing it, a topical antifungal, and a topical steroid. In those who do not improve following these measures oral antifungals and steroids may be used or the nail fold may be removed surgically.

Intertrigo is treated by addressing associated infections, by removing moisture from the site, and by using substances at the site to help maintain skin integrity. If the individual is overweight, losing weight may also help. Relapses of intertrigo are common.

Keeping the area of the intertrigo dry and exposed to the air can help prevent recurrences, as can removing moisture from the area using absorbent fabrics or body powders, including plain cornstarch and judiciously used antiperspirants.

Greases, oils, and barrier ointments, may help by protecting skin from moisture and from friction. Antifungal powders, most commonly clotrimazole 1%, may also be used in conjunction with a barrier ointment. Diaper rash ointment can also help.

Fungal infections associated with intertrigo may be treated with prescription antifungals applied directly to the skin (in most cases) or systemic antifungals, including fluconazole, nystatin, and griseofulvin.

Intertrigo is also a known symptom of vitamin B6 deficiency.

The United States Environmental Protection Agency (EPA) does not generally recommend sampling unless an occupant of the space has symptoms. Sampling should be performed by a trained professional with specific experience in mold-sampling protocols, sampling methods and the interpretation of findings. It should be done only to make a particular determination, such as airborne spore concentration or identifying a particular species. Before sampling, a subsequent course of action should be determined.

In the U.S., sampling and analysis should follow the recommendations of the Occupational Safety and Health Administration (OSHA), National Institute for Occupational Safety and Health (NIOSH), the EPA and the American Industrial Hygiene Association (AIHA).

Types of samples include air, surface, bulk, and swab. Air is the most common form of sampling to assess mold levels. Indoor and outdoor air are sampled, and their mold-spore levels compared. Air sampling often identifies hidden mold. Surface sampling measures the number of mold spores deposited on indoor surfaces, collected on tape or in dust. Bulk removal of material from the contaminated area is used to identify and quantify the mold in the sample. With swab, a cotton swab is rubbed across the area being sampled, often a measured area, and subsequently sent to the mold testing laboratory. Final results indicate mold levels and species located in suspect area.

Multiple types of sampling are recommended by the AIHA, since each has limitations; for example, air samples will not identify a hidden mold source and a tape sample cannot determine the level of contamination in the air.

The prognosis of SSSS in children is excellent, with complete resolution within 10 days of treatment, and without significant scarring. However, SSSS must be differentiated carefully from toxic epidermal necrolysis, which carries a poor prognosis. The prognosis in adults is generally much worse, and depends upon various factors such as time to treatment, host immunity, and comorbidities.

Management of these partial-thickness wounds has been influenced by the Winter principle of moist wound healing, which suggests that wounds heal more rapidly in a moist environment. Hydrocolloid dressings applied directly to these wounds prevent the evaporation of moisture from the exposed dermis and create a moist environment at the wound site that promotes cell migration.

Treatment of corns include paring of the lesions, which immediately reduces pain. Another popular method is to use a corn plaster, a felt ring with a core of salicylic acid that relieves pressure and erodes the hard skin. However, if an abnormal pressure source remains, the corn generally returns. If the source of any abnormal pressure is detected, this may be avoided, usually through a change to more comfortable footwear or with various types of shoe inserts or footwear with extra toe space. In extreme cases correcting gait abnormalities may be required. If no other treatment is effective, surgery may be performed.

Diagnosis is usually made on the clinical appearance without the need for a tissue biopsy. However, when biopsies have been taken, the histologic appearance is one of marked elongation and hyperparakeratosis of the filiform papillae and numerous bacteria growing on the epithelial surface.

Hairy tongue may be confused with hairy leukoplakia, however the latter usually occurs on the sides of the tongue and is associated with an opportunistic infection with Epstein–Barr virus on a background immunocompromise (almost always human immunodeficiency virus infection but rarely other conditions which suppress the immune system).

Rainscald normally heals on its own, however as the condition can spread to involve large areas, prompt treatment is recommended. Although some cases can be severe, most rain scald is minor and can be easily and cheaply treated at home naturally.

First groom the affected parts carefully, to remove any loose hair. Be extremely gentle, the area is very sore itchy and horses will very quickly get fidgety. Next shampoo the area, use warm water and a soft cloth or brush, and massage the lather through the coat as much as the horse will tolerate. It is best to use Neem shampoo here, as this will treat as well as clean, but any mild shampoo is fine. Remove as much water as possible and dry the horse off, either use a hair drier or let him/her stand in the sun until completely dry. It is important not to let the horse roll! The rain scald bacteria may be picked up from the soil.

When the horse is completely dry, gently brush off any more loose hair. Next apply a salve or cream containing a high percentage of neem oil, or even pure neem oil, to liberally coat the affected area. Rub it in using fingertips, massage the area as much as the horse will tolerate. This will be very greasy. Smooth the hair back down and apply a rug to keep the horse dry, this prevents the neem being washed off as well as protecting from more dampness issues. Turn the horse out as normal.

Check it every day, and reapply the neem salve/cream if it seems to have dried away. The area should remain greasy with neem. Every 2–3 days or so, go through and scrape/pick off as much of the scabs as possible without upsetting the horse or making it bleed, then reapply the neem. Typically there will be improvement in a few days, and in a week there'll be some sign of new hair growing back. More severe rain scald may take longer.

Once all the scabs are gone and there is new hair fuzz growing in all over, use neem shampoo to clean the area of greasy residue, and dry well. Keep the horse covered for some time after rain scald has been treated, particularly in wet weather. Do not allow the skin to remain damp. It is advisable to shampoo the horse after riding or exercising, to remove sweat, which may encourage rain scald conditions, and make sure the coat is completely dry afterwards.

This treatment works in many ways. First, shampooing cleans the area of any contaminants, remove a lot of loose hair and scabs, and the rubbing stimulates the circulation. The neem is an antifungal agent, and works to eliminate the bacteria that cause the infection. It soothes the irritation in the area, and its greasiness provides the ideal environment for the raw skin to heal and grow new hair. It also helps to soften and lift the scabs. The new hair cannot grow in until those scabs are removed from the surface, but they are very painful to pick and remove, and most horses are intolerant of this procedure. After the neem has soaked into these scabs they will come away much more freely, and soon new hair will grow through.

In conventional treatment, scabs are softened with benzoyl peroxide and chlorhexidine and removed in order to speed the healing process. In severe or chronic cases, penicillin and streptomycin are injected into the horse to kill the bacteria.

Typically the disease is not life-threatening, nor does it impact the welfare of the horse, so treatments are more for the owner's sake of mind and cosmetic appeal of the animal.

The diagnosis of harlequin-type ichthyosis relies on both physical examination and certain laboratory tests.

Physical assessment at birth is vital for the initial diagnosis of harlequin ichthyosis. Physical examination reveals characteristic symptoms of the condition especially the abnormalities in the skin surface of newborns. Abnormal findings in physical assessments usually result in employing other diagnostic tests to ascertain the diagnosis.

Genetic testing is the most specific diagnostic test for harlequin ichthyosis. This test reveals a loss of function mutation on the ABCA12 gene. This gene is important in the regulation of protein synthesis for the development of the skin layer. Mutations in the gene may cause impaired transport of lipids in the skin layer and may also lead to shrunken versions of the proteins responsible for skin development. Less severe mutations result in a collodion membrane and congenital ichthyosiform erythroderma-like presentation. ABCA12 is an ATP binding cassette (ABC) transporter, and is a member of a large family of proteins that hydrolyze ATP to transport cargo across membranes. ABCA12 is thought to be a lipid transporter in keratinocytes necessary for lipid transport into lamellar granules during the formation of the lipid barrier.

Biopsy of skin may be done to assess the histologic characteristics of the cells. Histological findings usually reveal hyperkeratotic skin cells, which leads to a thick, white and hard skin layer.

Sloughing of the epidermis and exposure of the dermal layer clinically characterize moist desquamation. Outside of medical therapy, when moist desquamation is seen in the setting of nuclear warfare, the condition is generally thought to be fatal.

The first step in assessment is to non-intrusively determine if mold is present by visually examining the premises; visible mold helps determine the level of remediation necessary. If mold is actively growing and visibly confirmed, sampling for its specific species is unnecessary.

Intrusive observation is sometimes needed to assess the mold level. This includes moving furniture, lifting (or removing) carpets, checking behind wallpaper or paneling, checking ventilation ductwork and exposing wall cavities. Detailed visual inspection and the recognition of moldy odors should be used to find problems. Efforts should focus on areas where there are signs of liquid moisture or water vapor (humidity), or where moisture problems are suspected.

"Warm water immersion foot" is a skin condition of the feet that results after exposure to warm, wet conditions for 48 hours or more and is characterized by maceration ("pruning"), blanching, and wrinkling of the soles, padding of toes (especially the big toe) and padding of the sides of the feet.

Foot maceration occur whenever exposed for prolong periods to moist conditions. Large watery blisters appear which are painful when they open and begin to peel away from the foot itself. The heels, sides and bony prominences are left with large areas of extremely sensitive, red tissue, exposed and prone to infection. As the condition worsens, more blisters develop due to prolonged dampness which eventually covers the entire heel and/or other large, padded sections of the foot, especially the undersides as well as toes. Each layer in turn peels away resulting in deep, extremely tender, red ulcerations.

Healing occurs only when the feet are cleansed, dried and exposed to air for weeks. Scarring is permanent with dry, thin skin that appears red for up to a year or more. The padding of the feet returns but healing can be painful as the nerves repair with characteristics of diabetic neuropathy. Antibiotics and/or antifungal are sometimes prescribed.

Foot immersion is a common problem with homeless individuals wearing one pair of socks and shoes for extensive periods of time, especially wet shoes and sneakers from rain and snow. The condition is exacerbated by excessive dampness of the feet for prolonged periods of time. Fungus and bacterial infections prosper in the warm, dark, wet conditions and are characterized by a sickly odor that is distinct to foot immersion.

Diagnosis is clinical. Sensation is tested using graded monofilament.

Often a diagnosis of exclusion, skin biopsy shows a neutrophillic inflammatory infiltrate.

Diagnosis is mainly clinical, based on the history and clinical appearance. The differential diagnosis includes other oral white lesions such as Leukoplakia, squamous cell carcinoma, oral candidiasis, lichen planus, white sponge nevus and contact stomatitis. In contrast to pseudomembraneous candidiasis, this white patch cannot be wiped off. Tissue biopsy is sometimes carried out to rule out other lesions, although biopsy is not routinely carried out for this condition.