Guide To The Causes, Risk Factors, And Transmission Of Ringworm

November 29, 2023

Ringworm, dermatophyte infection, and dermatophytosis are terms used to describe a skin infection caused by one of several types of fungi. Despite the name of the infection, no parasites cause an individual to develop ringworm. Symptoms of ringworm are dependent upon the location. When ringworm affects the skin, an individual may develop scaly, red, and itchy plaques on the skin. These plaques may form into pustules or blisters, and they may have a darker red color on their border that resembles a ring. When ringworm affects a patient's nails, they can experience discoloration, abnormal thickening, or may crack. When ringworm affects the scalp, bald patches may form. Diagnosis of ringworm is made with a physical examination with a blacklight, skin biopsy, fungal culture, and KOH or potassium hydroxide examination.

There are several options for ringworm treatment, and many of them vary based on the specific type. Athlete's foot treatment, for instance, often includes a topical antifungal cream. Some individuals will take oral medicine for ringworm, which is most often an oral antifungal. A good option for scalp ringworm is an antifungal shampoo. Of course, it is vital for individuals to understand the causes and transmission of this condition first to ensure that they receive the best treatment for ringworm.

Human To Human

In the United States, the most common source of ringworm infection is contact with other infected humans directly and by contact with objects belonging to another infected person. Direct skin contact allows the fungus to be transmitted to a new host without being killed off by external factors that would play some role if the fungus was transferred to an object before another host.

A common source of ringworm transmission between humans is participation in direct contact sports, including rugby, soccer, football, wrestling, lacrosse, and basketball. These sports can cause the transmission of ringworm because they involve a large amount of direct skin contact between two or more individuals. When children between four and eleven years old develop ringworm infection, it most often occurs on the scalp and face. Individuals who have compromised immune systems are at a greater risk of developing ringworm when they participate in any activity that involves contact with the skin of others.

Animal To Human

Ringworm can develop in animals and be spread to humans. Common sources of ringworm infection from animals to humans include contaminated household pets, cattle, cows, horses, and other farm animals. Small rodents, ferrets, rabbits, and guinea pigs can also become infected and spread ringworm to humans. Many individuals contract ringworm from grooming a cat or dog infected with the fungus. An individual who comes in contact with moist soil that could be contaminated from a farm animal or cattle is also at an increased risk of developing ringworm.

Individuals and pets who engage in hunting activities involving contact with any rodent are at a greater risk of developing ringworm. Individuals who have pets known to dig frequently in moist warm soil can contract a ringworm infection from their pet. Fleas can serve as vectors for the infectious arthrospores that cause a ringworm infection. Thus, pet owners who do not use flea protection on their pets or live in flea prone climates are at an increased risk of contracting ringworm.

Soil To Human

Most individuals contract ringworm from one of the previously discussed transmission methods. However, this condition can also spread from soil to humans. This can happen because some of the fungi responsible for this infection can live and infect soil. However, in order for humans to contract ringworm from the soil, they must have prolonged exposure to and contact with infected soil. In addition, many experts believe that the soil must also be highly contaminated, not just mildly, for transmission to occur. In most cases, animals will contract the infection from the soil and pass it on to humans instead.

Sharing With Infected Individuals

Sharing certain objects with someone infected with ringworm can cause an individual to contract the fungal infection. Objects in the home and public places that have been contaminated by someone infected with ringworm can allow for the easy transmission of the fungus to another individual. Everyday objects shared between individuals that are most often implicated in the transmission of ringworm include hairbrushes, sheets, pillowcases, tennis shoes, bath towels, razors, shower loofahs, sponges, and athletic gear.

Fungi that cause a ringworm infection tend to grow around the shaft of an individual's hair and on their superficial skin layers. The fungi produce infective arthrospores distributed in large numbers through the skin cells and hair shed from an infected individual's body. These arthrospores can stay infectious from several months to several years on nonliving objects, depending on their environment. Arthrospores cannot penetrate through dry and healthy skin but use the vulnerabilities of mucous membrane exposure and lacerations on the skin when they come in contact with the body.

Tight Clothing

An individual who is known to wear clothing that is constrictive, tight, and has poor ventilation is at a higher risk of contracting ringworm than an individual who does not. The most common type of ringworm infection that develops due to tight clothing is referred to as jock itch or tinea cruris. Jock itch describes when the ringworm infection affects the skin around the buttocks, inner thighs, and groin. This risk factor is most common among adolescent men.

Individuals who tend to wear tight closed-toe shoes are also at a greater risk of developing tinea pedis or athlete's foot, where the ringworm infection affects the foot. Individuals who do not wear socks with closed shoes and do not change their socks at least once a day are also more susceptible to contracting ringworm. Tight clothing generally allows the surface of the skin to retain more moisture in warm climates, and it produces friction between the skin and fabric that produces vulnerability for arthrospore penetration.

Warm Climate

One of the biggest risk factors for the development of ringworm in an individual is when they live in a hot and humid climate. Almost half of all ringworm infections are caused by a type of fungus referred to as T. rubrum. Most of the fungi responsible for ringworm can survive the best in warm and moist spots. Individuals who live in a hot and humid climate tend to sweat more frequently, which makes them more susceptible to the fungi because their skin is wet.

Individuals who live in a warm climate tend to use facilities meant for leisure, competitive swimming, or other water activities. This also puts them at an increased risk of contracting ringworm. Another reason why warm climates hold a greater risk of ringworm infection is that these areas tend to be crowded and more densely populated because of the desirable climate. The more contact an individual has with other people and objects used or touched by others, the greater their risk of contracting the fungus that causes ringworm.

Weak Immune System

Evidence shows that individuals with weak immune systems are more likely to contract a ringworm infection. In addition, a weak immune system may also allow the infection to thrive quite significantly before patients are able to seek treatment. Many conditions result in a weak immune system. However, an individual's immune system can weaken for several other reasons, such as increased stress. An underdeveloped immune system, such as in children, can also be weak. When an individual's immune system is weak, it becomes exhausted easier and cannot fight off potential infections. This is why immunocompromised patients who have ringworm also tend to have this condition longer, even when they are receiving treatment.

Shower After Sports

Athletes are at a particularly high risk for contracting ringworm. The most common type of ringworm in athletes, of course, is athlete's foot. The reason for this is that athletes sweat a fair amount and are more physically active than most individuals. Due to their increased risk of ringworm, athletes must take extra precautions to prevent it. One of the best ways to do this is to shower after playing sports or exercising. Showering after sports allows athletes to wash off their sweat and keep their skin clean and free of the fungi that can cause this condition. Of course, it is vital for them to dry their skin with a towel after they shower as well.

Change Undergarments And Socks

Two common locations for ringworm to develop are on the feet and in the groin area. Thus, individuals need to keep these areas clean and dry in order to reduce their risk of this infection. One effective method of doing so is to change undergarments and socks regularly. Ideally, they need to wear clean pairs of both each day. Usually, this is enough. However, individuals should also keep an extra pair of underwear and socks in their gym bag to change into after a workout. Combining this method with showering after sports or exercise is quite effective at preventing the development of ringworm.

Keep Skin Dry And Clean

Even if individuals do not have any significant risk factors for developing ringworm, they should still practice prevention methods. The simplest method, of course, is to keep skin dry and clean. This means drying off with a towel after swimming, both when they were swimming in a pool or in a lake. Individuals also need to dry off after they shower. This is especially important if they showered at the gym or another public facility. Drying their hands after washing them with soap and water is crucial too. Of course, when individuals garden regularly, they should be wearing gloves, but should still wash their hands once they are finished.

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