What Are Jock Itch Blisters?

Jock itch, also known as tinea cruris, is a type of fungal skin infection that causes an itchy, ring-shaped rash sometimes lined with tiny blisters. The rash develops in the moist skin folds of the groin, buttocks, inner thighs, and genitals.

Jock itch is treated with topical antifungals and, in severe cases, oral antifungals. Because of its appearance, it is occasionally mistaken for genital herpes.

This article describes the symptoms, causes, and treatment of jock itch, and how the condition differs from herpes.

What Are the Symptoms of Jock Itch?

Jock itch is a contagious fungal skin infection similar to ringworm (tinea corporis) and athlete's foot (tinea pedis). The fungus thrives on moist areas of skin, especially in the creases of the groin and buttocks.

Once an infection is established, the fungus will cause an itchy skin rash that spreads outward. If left untreated, the rash can spread to the upper thigh and anus, the scrotum in males, and the labia in females.

Symptoms of jock itch include:

• A ring-shaped rash with a well-defined border
  
• Reddish or brownish skin discoloration
• Tiny, weeping blisters around the perimeter of the rash
• Scaly, peeling, cracking, or flaking skin
• Itching or burning
• Tiny skin bumps caused by inflammation of hair follicles
  

Symptoms of jock itch usually appear between four and 14 days after contact with the fungi.

Are Jock Itch Blisters Contagious?

The fungus that causes jock itch can vary depending on the part of the world you live in. The type most commonly seen in North America is called Trichophyton rubrum. This same fungus can also cause athlete's foot, ringworm, and fungal nail infections.

Trichophyton rubrum is highly contagious, The infection is spread by fungal spores that fall from the body on dead skin cells. When the spores land on another person's body, the warmth and moisture in skin folds provide the ideal environment for the fungus to multiply and grow.

Jock itch can be spread in the following ways:

• From person-to-person by skin-to-skin contact
• Contact with contaminated sports clothing
• Shared towels and athletic gear (such as protective cups)

You can also infect yourself if you have athlete's foot by touching your toes and then your groin area.

Risk factors for jock itch include:

• Obesity (due to increased skin folds)
• Living in hot, humid climates
• Heavy sweating
• Wearing tight clothing
• Not changing your underwear frequently
• Infrequent showering
• Sharing towels or athletic gear
• Using public showers or locker rooms
• Having a weakened immune system

How Long Do Jock Itch Blisters Last?

If left untreated, jock itch can last for months and cause cracking, bleeding, and pain. It can also spread to the parts of the body, such as the feet or nails, and be even harder to treat.

This is especially true with fungal nail infections (tinea unguium). These are notoriously difficult to treat and can persist for years, causing nail disfiguration, cracking, pain, and nail loss.

If treated appropriately, jock itch will usually clear within three to four weeks.

How Do You Treat Jock Itch Blisters?

Jock itch is commonly treated with topical antifungal drugs. There are applied in a thin layer to the affected skin twice daily (morning and night) for up to eight weeks.

There are two classes of antifungals your healthcare provider may prescribe:

• Allylamine antifungals block an enzyme that the fungus needs to reproduce. The drugs tend to be more expensive but can usually clear the infection quicker. Options include Mentax (butenafine), Naftin (naftifine), and Lamisil (terbinafine).
• Azole antifungals block compounds used to build the cellular wall of fungi, causing the cell to die. Some of these are available over the counter and are appropriate for milder cases of jock itch. Options include Lotrimin (clotrimazole), Nizoral (ketoconazole), and Micatin (miconazole).

Oral antifungals are available for severe cases of jock itch. These include Lamisil (terbinafine) tablets taken once daily for up to six weeks and Sporanox (itraconazole) capsules taken twice daily for a week.

Improved hygiene is also crucial to clearing the infection. That means keeping the affected areas clean and dry as part of your daily routine.

What Are Other Causes of Blisters in the Groin Area?

Jock itch is commonly mistaken for genital herpes. Genital herpes can also cause tiny blisters around the inner thigh, buttocks, and anus, but they are ultimately two different infections caused by two different things.

Can You Prevent Jock Itch Blisters?

Jock itch is common but can be avoided by taking the following preventive steps:

• Shower or bathe regularly, particularly after sweating or exercising strenuously.
• Wash workout clothes, underwear, socks, and towels after each use.
• Keep the groin, inner thigh, and buttocks area clean and dry.
• Do not share clothing, sports equipment, or towels with other people.
• Put on your socks before putting on underwear if you have athlete's foot.
• Wear footwear in locker rooms and public showers.