Summer is time for fun in the sun, but spending a lot of time outdoors may put you at a greater risk for developing a skin rash. These rashes often develop from coming into contact with a variety of poisonous plants or spending too much time in the heat. Although most rashes are harmless and disappear on their own after a few hours, some can be more serious.

Rashes Caused by Plants

Poison ivy, oak and sumac are three of the most common plants that may lead to skin rashes. According to the Food and Drug Administration (FDA), the sap of these plants all contain a substance called urushiol, which can lead to irritation if it comes into contact with your skin. Dr. Sean Kenniff, health specialist for CBS News, says the most common characteristics of a poisonous plant reaction include:

• A red rash and extreme itching;
• A rash that is in streaks or patches (where the plant touched the skin);
• Red bumps or large blisters.

An allergic reaction from these plants usually occurs within a few days after the initial contact, and can last anywhere from one to three weeks. Although most of the rashes go away on their own, some reactions can be severe, requiring hospitalization.

Contrary to popular belief, these rashes cannot be spread from person to person – unless the person has urushiol on their hands or clothing and the urushiol comes into contact with his or her skin. The rash itself is not contagious.

If you do come into contact with any of these poisonous plants the FDA recommends washing the skin in cool water as soon as possible to prevent the urushiol from spreading to other areas of your body. Because the rash itself can be extremely itchy, you can try a cool shower, oatmeal bath or calamine lotion for relief.

More severe reactions occur when the urushiol comes into contact with mucous membranes (located in the eyes, nose, mouth and genitals). If the plant comes into contact with any of these areas you should consult with your doctor or practitioner.

The FDA offers a few tips for avoiding contact with these poisonous plants:

• Learn what the plants look like: Stay away from plants that have three larger leaves, with three smaller leaves each.
• Wash garden tools regularly: Many times people are not aware they are digging and planting in an area that is currently inhabited by these poisonous plants. To be on the safe side, wash all of your gardening tools after each use.
• Wear protective clothing: If you know you will be in an area that these poisonous plants are likely to live, where long pants, long sleeves, boots and gloves to keep your skin protected.
• Consult with your doctor or practitioner: If you have a difficult time avoiding poison ivy due to the nature of your work, there are many over-the-counter and herbal remedies that your doctor or practitioner can recommend to help prevent or reduce the severity of rashes from these plants.
  

Heat Rashes

Heat rashes are very common in the summer because they are caused by excessive sweating during hot, humid weather. However, you can also get a heat rash in the winter if you are overdressed. Heat rashes look like a cluster of pimples or blisters, and often occur on your neck, chest, groin, under breasts, and in elbow creases.

According to Dr. Sean Kiffner, health specialist for CBS News, when you perspire excessively it begins to build up and damages cells on the surface of the skin, forming a barrier and trapping sweat beneath the skin. The sweat continues to build up and eventually causes bumps on the surface of your skin. The prickly or stinging sensation you feel is caused by the bumps bursting and sweat being released.

Dr. Kiffner and the CDC offer a few suggestions for treating heat rashes:

• Provide a cooler, less humid environment: Take a cool bath or shower or sit in front of a fan or air conditioner.
• Keep the affected area dry: When you shower, air-dry your skin instead of rubbing it with a towel.
• Use powder: It may help with itching, but avoid using ointments and creams (they keep the skin warm and may worsen your condition);

The rash should go away on its own after a few days, but if the area becomes infected after the bumps burst, you should contact your doctor or practitioner.

Source: Food and Drug Administration; Center for Disease Control; CBSNews.com