Posted by & filed under Noah's Notes.

Most Mainers eagerly await the summer months when we can enjoy great warm weather activities in one of the most beautiful sates in the country. Whether it’s sports, fishing, boating, cycling, running, walking, camping or just relaxing outdoors, it is an energizing and fulfilling time of the year.

Of course, nothing is perfect and summertime also offers some unique and sometimes annoying skin conditions. Fortunately, most are not serious and are self-limited and most respond to treatments, but prevention can limit the impact that these rashes have on your summer fun.

heat rashHeat Rash (Prickly Heat): In hot and humid weather, excessive sweating can clog your pores, which leads to inflammation and swelling under the skin. This results in a pimply rash, often in skin creases, under the arms, in the groin, or anywhere where it is more difficult for perspiration to evaporate. You can help to avoid this by wearing looser fitting clothing, keeping your skin clean, and if you are prone to heat rash, try to stay in cooler areas during very hot and humid weather. Heat rash can be treated with cool compresses, over the counter hydrocortisone cream (if there is itching), and anti-inflammatory medications (ibuprofen, naproxen) or acetaminophen if there is burning or pain associated with the rash.


poison ivyPoison Ivy: Poison Ivy is one of the skin rashes known as contact dermatitis. In the case of poison ivy, the plant contains chemicals to which some people are highly allergic (I’m one of those people!). Interestingly, there are also people who will get no reaction to poison ivy. After coming in contact with the plant, these chemicals may remain on your hands or under your fingernails for more than a day, and they can also remain on your clothing.  The allergic reaction results in the development of very itchy, tiny blisters (called vesicles) on the skin, often grouped together and sometimes in lines. The vesicles can coalesce to form a blister, and all can leak inflammatory fluid. Contrary to popular belief, this fluid does not spread the rash, but the plant chemicals that remain on skin and clothing can lead to the spread of the rash for a few days after exposure. When the rash is limited it can be effectively treated with steroid creams, though it often requires prescription strength. If the rash is more widespread or if it involves the face or groin, taking prednisone orally is often necessary to manage the symptoms while the rash runs its course. Prevention, of course, involves knowing what the plant looks like and avoiding it if you are sensitive, which is why I do not go fiddle heading!


swimmer's itchSwimmer’s Itch: Knowledge about swimmer’s itch has become more widespread but I recall getting a phone call about 20 years ago from a confused ER physician in Boston, asking about a strange rash that a patient had developed after swimming in our area and then returning home. It felt good to help to educate this doctor at Massachusetts General Hospital! This unfortunate malady is caused by a tiny parasite (called schistosomes) that normally live in snails or water fowl. If you happen to be in the water when these parasites float by they may get on your skin and then burrow under, where they die. They cause no illness but the allergic reaction that follows can lead to very itchy, often red pimples or spots scattered on the parts of your body that were submerged at the time of exposure. These can occur within minutes of exposure or up to 12 hours later. Over the counter hydrocortisone cream, cool compresses, and anit-inflammatory drugs can help with itching. Diphenhydramine (Benadryl) can also help but may cause drowsiness. Vigorous toweling after leaving the water can help to prevent swimmer’s itch.


pslePolymorphous Light Eruption (PMLE): This rash (to which I am also susceptible) typically occursearly in the warm weather season during our first few exposures to more intense sunlight. Usually within hours the skin exposed to the sunlight develops small bumps (called papules) or spots (called plaques) that are itchy, though not as severely itchy as poision ivy. These tend to last for days to weeks and usually respond nicely to over the counter hydrocortisone cream. More severe cases may require stronger steroid creams to control the itching. Although this rash can sometimes look like poison ivy, there is typically no leaking of inflammatory fluid from the rash and it does not spread. PMLE can be avoided by limiting sun exposure early in the season (hats and long sleeves), and by using effective sunscreens. Once a person has had PMLE it typically may recur on the same areas of the skin and in the same manner in subsequent summer seasons if the skin is not protected.


There are, of course, a variety of other skin insults to which we subject ourselves in order to enjoy nice weather (black fly, mosquito and other insect bites, “wood poisoning”, etc.) and certain drugs, like some diuretics and antibiotics, can predispose you to a rash when you’re exposed to the sun. If you have a rash that concerns you or if a common rash appears to become infected you should see your primary care provider for advice.



I have not covered Lyme Disease and the rashes that can be associated with it because it is a much more serious topic that requires more in depth discussion.


Noah Nesin, MD

Dr. Nesin, Vice President of Medical Affairs for PCHC, is a family doctor with 30 years of experience.

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