The skin protects the body by acting as the first line of defense against infection. An infection is the invasion of body tissues by disease-causing microorganisms, their multiplication and the reaction of body tissues to these microorganisms and the toxins that they produce. Infections are caused by microorganisms such as viruses, prions, bacteria, and viroids, although larger organisms like macroparasites and fungi can also cause infection. Hosts normally fight infections themselves via their immune system. The human body reacts to infections with an innate response, often involving inflammation, followed by an adaptive response. Pharmaceuticals can also help fight infections. Infections of the integumentary system include athlete's foot and herpes simplex.
Athlete's foot (also known as ringworm of the foot) is a fungal infection of the skin that causes scaling, flaking, and itching of affected areas. It is caused by fungi in the genus Trichophyton. It is typically transmitted in moist areas where people walk barefoot, such as showers or swimming pools. Although the condition typically affects the feet, it can spread to other areas of the body, including the groin, where it is called jock itch. Athlete's foot can be treated by a number of pharmaceutical creams, as well as with oral antifungals. Hygiene plays an important role in managing an athlete's foot infection. Since fungi thrive in moist environments, keeping feet and footwear as dry as possible and avoiding sharing towels aids prevention of primary infection.
Herpes simplex (Greek for "creeping") is a viral disease caused by both Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). Infection with the herpes virus is categorized into one of several distinct disorders based on the site of infection. Oral herpes, the visible symptoms of which are colloquially called cold sores or fever blisters, is an infection of the face or mouth . Oral herpes is the most common form of infection. Genital herpes, known simply as herpes, is the second most common form of herpes. Herpes simplex is most easily transmitted by direct contact with a lesion or the body fluid of an infected individual. Transmission may also occur through skin-to-skin contact during periods of asymptomatic virus shedding. Barrier protection methods are the most reliable method of preventing transmission of herpes, but they merely reduce rather than eliminate risk. Condom use reduces the transmission risk of herpes simplex significantly. Condom use is much more effective at preventing male to female transmission than vice-versa.