It may have a variety of appearances; most easily identifiable are the enlarging raised red rings with a central area of clearing (ringworm). The same appearances of ringworm may also occur on the scalp (tinea capitis), beard area (tinea barbae) or the groin (tinea cruris, known as jock itch or dhobi itch).

Other classic features of tinea corporis include:

- The edge of the rash appears elevated and is scaly to touch.

- Sometimes the skin surrounding the rash may be dry and flaky.

- Almost invariably, there will be hair loss in areas of the infection.

Skin infections and wrestling is the role of skin infections in wrestling. This is an important topic in wrestling since breaks in the skin are easily invaded by bacteria or fungi and wrestling involves constant physical contact that can cause transmission of viral, bacterial, and fungal pathogens. These infections can also be spread through indirect contact, for example, from the skin flora of an infected individual to a wrestling mat, to another wrestler. According to the National Collegiate Athletic Association's (NCAA) Injury Surveillance System, ten percent of all time-loss injuries in wrestling are due to skin infections.

Tinea corporis (also known as ringworm, tinea circinata, and tinea glabrosa) is a superficial fungal infection (dermatophytosis) of the arms and legs, especially on glabrous skin; however, it may occur on any part of the body. It is similar to other forms of tinea.

Bacterial infections, or pathogens, make up the largest category of include Furuncles, Carbuncles, Folliculitis, Impetigo, Cellulitis or Erysipelas, and Staphylococcal disease. These range in severity, but most are quickly identified by irritated and blotchy patches of skin. Bacterial infections, of all skin infections, are typically the easiest to treat, using a prescribed anti-bacterial lotion or crème.

Molluscum Contagiosum is caused a DNA poxvirus called the molluscum contagiosum virus. For adults, molluscum infections are often sexually transmitted, but in wrestling, it is spread either through direct contact or through contact with shared items such as gear or towels. Molluscum Contagiosum can be identified by pink bulbous growths that contain the virus. These typically grow to be 1–5 millimeters in diameter, and last from 6 to 12 months without treatment and without leaving scars. Some growths may remain for up to 4 years. Treatment for Molluscun Contagiosum must be

designated by a healthcare professional because they can be dangerous. Usually

for treatment liquid nitrogen can be used to freeze the molluscum off but other methods include other creams that burn the warts off, or oral medications.

The herpes simplex virus comes in two different strains, though only one is spread among wrestlers. Type 1 (HSV-1) can be transmitted through contact with an infected individual, and usually associated with sores on the lips, mouth, and face. HSV-1 can also cause infection of the eye, or even infection of the lining of the brain, known as meningoencephalitis. The lesions will heal on their own in 7 to 10 days, unless the infected individual has a condition that weakens the immune system. Once an infection occurs, the virus will spread to nerve cells, where it remains for the rest of the person’s life. Occasionally, the virus will suddenly display recurring symptoms, or flares. There is no complete treatment for Herpes Simplex 1 but there is prescription medication to help ease and relieve the symptoms of the virus. Antiviral oral medication and topic medication can be prescribed to relieve the pain and soreness of the herpes virus.

Verrucae are small skin lesions which can be found on the bottom surface of the foot. They vary in length, from one centimeter in diameter upwards. Verrucae are caused by the human papilloma virus, which is common in all environments but does often attack the skin. The color of the lesion is usually paler then the normal tone of the skin, and is surrounded by a thick layer of calloused skin. Depending on the development of the Verrucae, the surface may show signs of blood vessels, which feed the infection.

Tinea infections, more commonly known as Ringworm, are the most common skin infections transmitted through wrestling. It is caused by parasitic fungi that survive on keratin, an organic material that is found in skin, hair, and nails. There are several varieties of Tinea, which are classified depending on their location. Tinea corporis is found on the body, tinea cruris (jock itch) on the groin, tinea capitis on the scalp, and tinea pedis (athlete’s foot) on the foot. Although they are not harmful, they are highly contagious and difficult to treat. The symptoms of ringworm include patches of skin that are red, swollen, and irritated, forming the shape of a ring. Ringworm will last between two and four weeks with treatment. Tinea infections can be combatted orally or topically with numerous different medications. Some topical treatments include Mentax 1%, Lamisil 1%, Naftin 1% and Spectazole and these creams should be applied two times a day until the infection is gone. Oral treaments for Tinea include Lamisil, Sporanox, and Diflucan.

Id reactions (also known as "disseminated eczema," and "generalized eczema") are types of acute dermatitis developing after days or weeks at skin locations distant from the initial inflammatory or infectious site. They can be localised or generalised. This is also known as an 'autoeczematous response' and there must be an identifiable initial inflammatory or infectious skin problem which leads to the generalised eczema. Often, intensely itchy, the red papules and pustules can also be associated with blisters and scales and are always remote from the primary lesion. It is most commonly a blistering rash with itchy vesicles on the sides of fingers and feet as a reaction to fungal infection on the feet, athlete's foot. Stasis dermatitis, Allergic contact dermatitis, Acute irritant contact eczema and Infective dermatitis have been documented as possible triggers, but the exact cause and mechanism is not fully understood. Several other types of id reactions exist including erythema nodosum, erythema multiforme, Sweet's syndrome and urticaria.

A skin and skin structure infection (SSSI), also referred to as skin and soft tissue infection (SSTI) or acute bacterial skin and skin structure infection (ABSSSI), is an infection of skin and associated soft tissues (such as loose connective tissue and mucous membranes). The pathogen involved is usually a bacterial species. Such infections often requires treatment by antibiotics.

Until 2008, two types were recognized, complicated skin and skin structure infection (cSSSI) and uncomplicated skin and skin structure infection (uSSSI). "Uncomplicated" SSSIs included simple abscesses, impetiginous lesions, furuncles, and cellulitis. "Complicated" SSSIs included infections either involving deeper soft tissue or requiring significant surgical intervention, such as infected ulcers, burns, and major abscesses or a significant underlying disease state that complicates the response to treatment. Superficial infections or abscesses in an anatomical site, such as the rectal area, where the risk of anaerobic or gram-negative pathogen involvement is higher, should be considered complicated infections. The two categories had different regulatory approval requirements. The uncomplicated category (uSSSI) is normally only caused by "Staphylococcus aureus" and "Streptococcus pyogenes", whereas the complicated category (cSSSI) might also be caused by a number of other pathogens. In cSSSI, the pathogen is known in only about 40% of cases.

Because cSSSIs are usually serious infections, physicians do not have the time for a culture to identify the pathogen, so most cases are treated empirically, by choosing an antibiotic agent based on symptoms and seeing if it works. For less severe infections, microbiologic evaluation via tissue culture has been demonstrated to have high utility in guiding management decisions. To achieve efficacy, physicians use broad-spectrum antibiotics. This practice contributes in part to the growing incidence of antibiotic resistance, a trend exacerbated by the widespread use of antibiotics in medicine in general. The increased prevalence of antibiotic resistance is most evident in methicillin-resistant "Staphylococcus aureus" (MRSA). This species is commonly involved in cSSSIs, worsening their prognosis, and limiting the treatments available to physicians. Drug development in infectious disease seeks to produce new agents that can treat MRSA.

Since 2008, the U.S. Food and Drug Administration has changed the terminology to "acute bacterial skin and skin structure infections" (ABSSSI). The Infectious Diseases Society of America (IDSA) has retained the term "skin and soft tissue infection".

Causes include infection with dermatophytosis, Mycobacterium, viruses, bacteria and parasites. Eczematous conditions including contact allergic dermatitis and stasis dermatitis as well as stitches and trauma have also been associated with id reactions. Radiation treatment of tinea capitis has been reported as triggering an id reaction.

"Erythema migrans is the only manifestation of Lyme disease in the United States that is sufficiently distinctive to allow clinical diagnosis in the absence of laboratory confirmation." It is a pathognomonic sign: a physician-identified rash warrants an instant diagnosis of Lyme disease and immediate treatment without further testing, even by the strict criteria of the Centers for Disease Control and Prevention. Such target lesions (bull's-eye rashes) are characteristic of "Borrelia" infections, and no other pathogens are known that cause this form of rash. It is also true, though, that the rash in Lyme disease may also be solid rather than bullseye-shaped, so self-diagnosis cannot rule out Lyme disease, and a doctor visit is advisable.

The erythema migrans rash is classically 5 to 6.8 cm in diameter, appearing as an annular homogenous erythema (59%), central erythema (30%), central clearing (9%), or central purpura (2%). Because of the "bull's-eye" description to describe the Lyme disease rash, the condition commonly called ringworm is sometimes confused with Lyme disease. Uncommonly, EM may be less than 5 cm in diameter. Multiple painless EM rashes may occur, indicating disseminated infection.

The EM rash occurs in 80% to 90% of those infected with "Borrelia". A systematic review of the medical literature showed 80% of patients have an expanding EM rash, at the site of the tick bite, although some patients with EM do not recall a tick bite. In endemic areas of the United States, homogeneously red rashes are more frequent.

Advocates of a diagnosis called "chronic lyme disease" dispute the generally accepted incidence of the rash, claiming it occurs in less than 50% of infections.

An opportunistic infection is an infection caused by pathogens (bacteria, viruses, fungi, or protozoa) that take advantage of an opportunity not normally available, such as a host with a weakened immune system, an altered microbiota (such as a disrupted gut flora), or breached integumentary barriers. Many of these pathogens do not cause disease in a healthy host that has a normal immune system. However, a compromised immune system, a penetrating injury, or a lack of competition from normal commensals presents an opportunity for the pathogen to infect.

A hot spot, or "acute moist dermatitis", is an acutely inflamed and infected area of skin irritation created and made worse by a dog licking and biting at itself. A hot spot can manifest and spread rapidly in a matter of hours as secondary Staphylococcus infection causes the top layers of the skin to break down and as pus becomes trapped in the hair. Hot spots can be treated with corticosteroid medications and oral as well as topical antibiotic application, as well as clipping hair from around the lesion. Underlying inciting causes include flea allergy dermatitis, ear disease or other allergic skin diseases. Dogs with thick undercoat are most subject to getting hot spots.

The infection causes a red, intensely pruritic (itchy) eruption. The itching can become very painful and if scratched may allow a secondary bacterial infection to develop. Cutaneous larva migrans usually heals spontaneously over weeks to months and has been known to last as long as one year. However, the severity of the symptoms usually causes those infected to seek medical treatment before spontaneous resolution occurs. Following proper treatment, migration of the larvae within the skin is halted and relief of the associated itching can occur in less than 48 hours (reported for thiabendazole).

This is separate from the similar cutaneous larva currens which is caused by "Strongyloides". Larva currens is also a cause of migratory pruritic eruptions but is marked by 1) migratory speed on the order of inches per hour 2) perianal involvement due to autoinfection from stool and 3) a wide band of urticaria.

Cutaneous larva migrans (abbreviated CLM) is a skin disease in humans, caused by the larvae of various nematode parasites of the hookworm family (Ancylostomatidae). The most common species causing this disease in the Americas is "Ancylostoma braziliense". These parasites live in the intestines of dogs, cats, and wild animals and should not be confused with other members of the hookworm family for which humans are definitive hosts, namely "Ancylostoma duodenale" and "Necator americanus".

Colloquially called creeping eruption due to its presentation, the disease is also somewhat ambiguously known as "ground itch" or (in some parts of the Southern USA) "sandworms", as the larvae like to live in sandy soil. Another vernacular name is plumber's itch. The medical term CLM literally means "wandering larvae in the skin".

The first sign of a foot-rot infection is when the skin between the claws of the hoof begins to swell (cellulitis). Swelling usually appears 24 hours after infection. The skin between the toes may be very red and tender and the toes may separate because of all the swelling. This is very painful to the animal and can cause lameness. The animal may also have a raised body temperature. A crack can develop along the infected part and is yellow in color. The foot will have a foul odor. Tendons and joints in the area can become infected, which is much harder to treat. A condition known as "super foot rot" is seen in some animals. Super foot rot infection occurs much faster and is usually much more severe. Most normal foot rot treatments will not cure this foot rot and a veterinarian should be contacted immediately.

Vaccines have been developed, but their efficacy is questionable and the immunity they provide is of short duration.

Herpes gladiatorum is one of the most infectious of herpes-caused diseases, and is transmissible by skin-to-skin contact. The disease was first described in the 1960s in the "New England Journal of Medicine". It is caused by contagious infection with human herpes simplex virus type 1 (HSV-1), which more commonly causes oral herpes (cold sores). Another strain, HSV-2 usually causes genital herpes, although the strains are very similar and either can cause herpes in any location.

While the disease is commonly passed through normal human contact, it is strongly associated with contact sports—outbreaks in sporting clubs being relatively common.

Other names for the disease are herpes rugbiorum or "scrumpox" (after rugby football), "wrestler's herpes" or "mat pox" (after wrestling). In one of the largest outbreaks ever among high-school wrestlers at a four-week intensive training camp, HSV was identified in 60 of 175 wrestlers. Lesions were on the head in 73 percent of the wrestlers, the extremities in 42 percent, and the trunk in 28 percent. Physical symptoms sometimes recur in the skin. Previous adolescent HSV-1 seroconversion would preclude most herpes gladiatorum, but being that stress and trauma are recognized triggers, such a person would be likely to infect others.

Pemphigus foliaceus is the most common autoimmune disease of the dog. Blisters in the epidermis rapidly break to form crusts and erosions most often affecting the face and ears initially, but in some cases spreading to include the whole body. The pawpads can be affected causing marked hyperkeratosis (thickening of the pads with scale). Other autoimmune diseases include bullous pemphigoid and epidermolysis bullosa acquisita.

Treatment of autoimmune skin conditions requires treatment to markedly reduce the abnormal immune response; steroids, azathoprine and other drugs are used as immunosuppressive agents.

Herpes gladiatorum is characterized by a rash with clusters of sometimes painful fluid-filled blisters, often on the neck, chest, face, stomach, and legs. The infection is often accompanied by lymphadenopathy (enlargement of the lymph nodes), fever, sore throat, and headache. Often, the accompanying symptoms are much more of an inconvenience than the actual skin blisters and rash.

Each blister contains infectious virus particles (virions). Close contact, particularly abrasive contact as found in contact sports, causes the infected blisters to burst and pass the infection along. Autoinoculation (self-infection) can occur through self-contact, leading to infection at multiple sites on the body.

Herpes gladiatorum symptoms may last up to a few weeks, and if they occur during the first outbreak, they can be more pronounced. In recurrences of the ailment, symptoms are milder, even if lesions still tend to occur. With recurrent infections scabs may form at 3 days yet the lesions are still considered infectious up til 6.4 days after starting oral antiviral medications. Healing takes place without leaving scars. It is possible that the condition evolves asymptomatically and sores are never present.

Vulvitis, inflammation of the vulva, can have a variety of etiologies in children and adolescents, including allergic dermatitis, contact dermatitis, lichen sclerosus, and infections with bacteria, fungi, and parasites. Dermatitis in infants is commonly caused by a soiled diaper being left on for an extended period of time. Increasing the frequency of diaper changes and topical application of emollients are sufficient to resolve most cases. Dermatitis of the vulva in older children is usually caused by exposure to an irritant (e.g. scented products that come into contact with the vulva, laundry detergent, soaps, etc.) and is treated with preventing exposure and encouraging sitz baths with baking soda as the vulvar skin heals. Other treatment options for vulvar dermatitis include oral hydroxyzine hydrochloride or topical hydrocortisone.

Lichen sclerosus is another common cause of vulvitis in children, and it often affects an hourglass or figure eight-shaped area of skin around the anus and vulva. Symptoms of a mild case include skin fissures, loss of skin pigment (hypopigmentation), skin atrophy, a parchment-like texture to the skin, dysuria, itching, discomfort, and excoriation. In more severe cases, the vulva may become discolored, developing dark purple bruising (ecchymosis), bleeding, scarring, attenuation of the labia minora, and fissures and bleeding affecting the posterior fourchette. Its cause is unknown, but likely genetic or autoimmune, and it is unconnected to malignancy in children. If the skin changes are not obvious on visual inspection, a biopsy of the skin may be performed to acquire an exact diagnosis. Treatment for vulvar lichen sclerosus may consist of topical hydrocortisone in mild cases, or stronger topical steroids (e.g. clobetasol propionate). Preliminary studies show that 75% of cases do not resolve with puberty.

Organisms responsible for vulvitis in children include pinworms ("Enterobius vermicularis"), "Candida" yeast, and group A hemolytic "Streptococcus". Though pinworms mainly affect the perianal area, they can cause itching and irritation to the vulva as well. Pinworms are treated with albendazole. Vulvar "Candida" infections are uncommon in children, and generally occur in infants after antibiotic therapy, and in children with diabetes or immunodeficiency. "Candida" infections cause a red raised vulvar rash with satellite lesions and clear borders, and are diagnosed by microscopically examining a sample treated with potassium hydroxide for hyphae. They are treated with topical butoconazole, clotrimazole, or miconazole. "Streptococcus" infections are characterized by a dark red discoloration of the vulva and introitus, and cause pain, itching, bleeding, and dysuria. They are treated with antibiotics.

Plasma cell cheilitis is a very rare presentation of a condition which more usually occurs on the gingiva (termed "plasma cell gingivitis") or sometimes the tongue. Plasma cell cheilitis appears as well defined, infiltrated, dark red plaque with a superficial lacquer-like glazing. Plasma cell cheilitis usually involves the lower lip. The lips appear dry, atrophic and fissured. Angular cheilitis is sometimes also present.

Fifth disease starts with a low-grade fever, headache, rash, and cold-like symptoms, such as a runny or stuffy nose. These symptoms pass, then a few days later the rash appears. The bright red rash most commonly appears in the face, particularly the cheeks. This is a defining symptom of the infection in children (hence the name "slapped cheek disease"). Occasionally the rash will extend over the bridge of the nose or around the mouth. In addition to red cheeks, children often develop a red, lacy rash on the rest of the body, with the upper arms, torso, and legs being the most common locations. The rash typically lasts a couple of days and may itch; some cases have been known to last for several weeks. Patients are usually no longer infectious once the rash has appeared.

Teenagers and adults may present with a self-limited arthritis. It manifests in painful swelling of the joints that feels similar to arthritis. Older children and adults with fifth disease may have difficulty in walking and in bending joints such as wrists, knees, ankles, fingers, and shoulders.

The disease is usually mild, but in certain risk groups it can have serious consequences:

- In pregnant women, infection in the first trimester has been linked to hydrops fetalis, causing spontaneous miscarriage.

- In people with sickle-cell disease or other forms of chronic hemolytic anemia such as hereditary spherocytosis, infection can precipitate an aplastic crisis.

- Those who are immuno-compromised (HIV/AIDS, chemotherapy) may be at risk for complications if exposed.

Foot rot, or infectious pododermatitis, is a hoof infection commonly found in sheep, goats, and cattle. As the name suggests, it rots away the foot of the animal, more specifically the area between the two toes of the affected animal. It is extremely painful and contagious. It can be treated with a series of medications, but if not treated, the whole herd can become infected. The cause of the infection in cattle is two species of anaerobic bacteria, "Fusobacterium necrophorum" and "Bacteroides melaninogenicus". Both bacteria are common to the environment in which cattle live, and "Fusobacterium" is present in the rumen and fecal matter of the cattle. In sheep, "F. necrophorum" first invades the interdigital skin following damage to the skin, and causes interdigital lesions and slight inflammation. The second stage of the disease is marked by the invasion of the foot by the foot rot bacterium "Dichelobacter nodosus", a Gram-negative anaerobe. Usually, an injury to the skin between the hooves allows the bacteria to infect the animal. Another cause of foot rot may be high temperatures or humidity, causing the skin between the hooves to crack and let the bacteria infect the foot. This is one of the reasons foot rot is such a major problem in the summer. Foot rot is easily identifiable by its appearance and foul odor. Treatment is usually with an antibiotic medication, and preventing injury to the feet is the best way to prevent foot rot.

The disease is different in cattle and sheep and cross-infection is not thought to occur.

Infectious bovine keratoconjunctivitis, or IBK, is a veterinary infection of cattle caused by "Moraxella bovis", a Gram-negative, β-haemolytic, aerobic, rod-shaped bacterium. It is spread by direct contact or by flies serving as vectors. It is the most common ocular disease of cattle (mostly beef). IBK is similar to human pink eye and causes severe infection of the conjunctiva, edema, corneal opacity, and ulceration. This disease is highly contagious and occurs worldwide. Younger animals are more susceptible, but recovery with minimal damage is usual, if they are treated early. The disease is also known as pinkeye, New Forest eye or blight.

The symptoms of an infection depend on the type of disease. Some signs of infection affect the whole body generally, such as fatigue, loss of appetite, weight loss, fevers, night sweats, chills, aches and pains. Others are specific to individual body parts, such as skin rashes, coughing, or a runny nose.

In certain cases, infectious diseases may be asymptomatic for much or even all of their course in a given host. In the latter case, the disease may only be defined as a "disease" (which by definition means an illness) in hosts who secondarily become ill after contact with an asymptomatic carrier. An infection is not synonymous with an infectious disease, as some infections do not cause illness in a host.

The bacteria invade the lacrimal glands of the eye, causing keratitis, uveitis, and corneal ulceration. Cattle show signs of pain, increased lacrimation, excessive blinking, and conjunctivitis. More severe cases may show systemic signs such as anorexia and weight loss. Chronic untreated cases can become blind. Diagnosis is usually based on the clinical signs, but the bacteria can be cultured from lacrimal swabs, or visualised on smears of lacrimal secretions.

Initially red to pink, flat spots (formally, "macules") and raised bumps (formally, "papules") may be seen on the skin.

Once fully developed, the classic appearance is "non-blanching, palpable purpura". This appears as deep red to purple spots that feel raised to the touch. Purpura refers to the red-purple discolored spots, while palpable implies that these spots can be felt as raised from the surrounding skin. Additionally, when gently pressed, the color does not fade to a lighter color ("non-blanching"). The red-purple color of the lesions is due to the inflammation in the blood vessels causing red blood cells to escape into the dermis skin layer.

Small fluid-filled blisters (or "vesicles"), pus-filled bumps resembling a pimple (or "pustules"), or shallow ulcers may also develop but are less common.

The location of skin lesions varies but are most commonly found symmetrically below the waist, primarily on the buttocks and legs. Other distributions include localized areas on the upper body or over several areas of the body.

With treatment, the lesions typically resolve in weeks to months and leave behind flat spots that are darker than the surrounding skin. (see "Postinflammatory hyperpigmentation" on "Hyperpigmentation")

A portion of cases may be persistent or recurrent. This tends to occur when the vasculitis is associated with chronic conditions such as connective tissue diseases.