Dermatophytes are a group of parasitic, microscopic fungi that metabolize keratin, a major protein found in hair, nails and certain skin cells. They cause a number of disorders in humans, including athlete's foot, ringworm and jock itch. Dermatophyte infections are highly contagious and an infected person can even transfer the infection from one body part to another. Knowing the symptoms of jock itch can help you determine whether an over-the-counter treatment can cure the problem or whether you should see a doctor.
Rash
The jock itch rash affects the groin area of both men and women. Men tend to have more cases of tinea cruris, the medical name for jock itch. Mayo Clinic reports that those with diabetes, those with impaired immune systems or who are obese tend to contract jock itch more often than others. The fungus does not need light to survive. In fact, it prefers warm, moist, dark places. Because there are many sweat ducts in the groin area and tiny amounts of perspiration are continually being released, the area has a constant supply of moisture.
Assuming you generally remain clothed, the fungus also appreciates the darkness in the groin area. Finally, the fungus finds warmth in the groin area. The heat supplied by your body, compounded by tight underclothes or clothes that are made of synthetic fibers inhibit air flow in that region.
The rash generally spreads over the groin, in the upper, inner thigh area and, in some cases, between the buttocks and around the anus. It rarely infects the penis or scrotum. It appears as a slightly raised red rash with well-defined borders.
Itch
Dermatophytes do not eat in the mechanical, chewing sense. Keratin is the dermatophytes' preferred meal. They metabolize keratin by releasing an enzyme that breaks it down. The enzyme and their metabolic wastes cause the immune system to initiate an allergic reaction. This reaction includes local inflammation and itch.
Other Symptoms
When a jock itch rash appears, the skin may show signs of flaking, peeling or cracking in the area, particularly on the borders of the rash. When a dermatophyte infection is severe, or in cases where skin is particularly sensitive, jock itch can cause a feeling of localized burning in the affected area and in some cases, blisters develop.
