The body normally serves as host for a variety of bacteria and fungi. Most of the time, the balance between the body as host and the microorganisms is maintained. However, there are times when the physiological, biochemical, and/or environmental conditions permit the microorganisms to tip that balance, thereby causing an infection.
Foot infections can be difficult problems for physicians to treat because of the biomechanical complexities of the extremity and the underlying circumstances that cause the infections. Soft tissue infections in the foot consist of any infectious process affecting the skin, subcutaneous tissue, adipose tissue, superficial or deep fascia, ligaments, tendons, tendon sheaths, joints, and/or joint capsules. Considering that there are more than 20 joints, 44 tendons, approximately 100 ligaments, 4 major compartments, and numerous fascial planes in the normal foot, the potential for complex problems is high.
Bacterial infections of the feet can occur as collections of pus, such as an abscess following a puncture wound or an infected hair follicle. These types of infections are usually red and elevated, and sometimes can be mistaken for an insect bite. There are many types of bacteria that cause an abscess, but staph are a leading cause. Bacterial skin infections can also resemble a rash, appearing as a reddened, tender, and warm area of skin. This type of infection is called cellulitis and can spread quickly, leading to red streaks that move from the foot toward the leg. The appearance of streaks is known as lymphangitis, which means the infection is spreading toward the lymph nodes. Cellulitis and lymphangitis can be caused by a variety of types of bacteria, but staph and sometimes streptococcus are the most common causes. Any infection, especially cellulitis and lymphangitis, requires prompt medical attention to avoid further spreading and complications. If left untreated, then some infections can spread to deeper tissues, including bone.
Certain fungal infections of the skin known as tinea infections are caused by dermatophytes, which are members of the Trichophyton, Microsporum, and Epidermophyton species. These mold-like fungi thrive in warm, moist areas, thriving on the dead tissues of hair, nails, and outer skin layers. Tinea infections include tinea pedis, known as athlete's foot; tinea corporis, known as ringworm; tinea capitis, a fungal infection of the scalp that can cause hair loss; tinea cruris, known as jock itch or tinea of the groin; tinea unguum, which is tinea of the nails; and tinea versicolor, a superficial fungal infection that produces brown, tan, or white spots on the trunk of the body. Tinea infections are contagious and can be passed through direct contact or by contact with clothing, from shower and pool surfaces, and even from pets.
Athlete's foot or tinea pedis is by far the most common form, with more than 12 million people in the United States suffering from the disease per year. It presents with redness, itching, burning, cracking, scaling, swelling, and occasionally bleeding. Athlete's foot includes toe web infections, moccasin type infections, and vesicular type infections. The condition generally includes small vesicles, fissures, scaling, maceration, hyperkeratinization, and eroded areas between the toes and on the plantar surface of the foot, as well as on other skin areas. For example, the nails may show thickening, pitting, and subungal debris.
Reoccurrences of the infection are frequent. For some subjects, such as those also diagnosed with diabetes or circulatory problems, or obese subjects, tinea infections and their treatment can be quite serious. The source of the affliction often is a public safety and health concern, as the occurrence of tinea pedis is higher in public areas such as locker rooms, public showers, sports facilities, and the like.
Moreover, there are at least 3 different types of nail infections caused by fungi. The most common infection is frequently caused by Trichophyton rubrum and affects the nail bed and the area beneath the nail. Another type of infection affects only the nail surface and creates white or light colored patches. This second type of fungal infection is unusual and represents only about 10% of the reported cases. A third type of fungal infection affects the nail root and usually afflicts persons with impaired immune defense. A fourth (and unusual) type is caused by an infection of yeast fungi. Infections by yeast most often only affect nails that already are infected or damaged in some way.
The fungi are invasive to the keratin nail tissue. Apart from becoming discolored and brittle, the nail may often separate from the nail bed. In addition, pain and difficulty in wearing foot apparel is often experienced. Initially, the disease affects only one nail, typically one nail of the foot, and is thereafter spread to more nails. The palms of the hands and the soles of the feet may frequently be affected as well. When the skin is affected, red spots frequently occur and the skin may peel off. Nail fungal infections are one of the hardest forms of external infection to treat, of which infections of toe nails are the most difficult to treat.
Despite advances in the understanding of the pathology of bacterial infections and fungal infections, there is still a need for compositions and methods that efficiently treat or prevent the progression and reoccurrence of bacterial infections and/or fungal infections that affect at least part of one or both feet.