Sun’s out, watch out: Medical conditions impacted by summertime heat and sun

A man smiles in the sun with a small towel around his neck after enjoying some exercise outside.

When most people think of summer, they imagine long days, flip-flops, and fun in the sun. However, too much fun in the sun can be a problem.

Prolonged exposure to the direct sunlight and higher temperatures that occur during the summer season can have a negative effect on people living with certain chronic health conditions.

While everyone should be mindful about staying hydrated and applying sunscreen, if you have any of the conditions our pharmacists outlined below, you’ll want to exercise additional caution.


Migraines can be triggered by many things, including dehydration. It’s much easier to get dehydrated when you’re out in the summer heat. If you suffer from migraines, make sure to drink plenty of extra water or beverages high in electrolytes throughout the day.

Migraines can also make you incredibly sensitive to light, which means if you have an attack, you might need to take extra steps to avoid the summer sun. If you feel a migraine coming on, try to spend time in a quiet, dark room. If you must go outside, protect yourself with an umbrella, a hat, and sunglasses.

Multiple sclerosis

If you have multiple sclerosis (MS), the arrival of summer also means an uptick in the chance you will experience the effects of Uhthoff’s phenomenon. This is when MS symptoms are worsened due to the body becoming overheated, which can be caused by too much sun, excessive exercise, or time spent in hot tubs.

Even a small increase in body temperature can aggravate your symptoms, so if you have MS, try to stay as cool as possible when temperatures rise. This can mean anything from wearing more lightweight clothing to drinking cold water. You should also always have a strategy to get inside to an air-conditioned environment if it’s too hot outside.


Most of us are aware of the harmful effects of ultraviolet (UV) light — but if you have lupus, too much UV exposure can be especially dangerous. Lupus increases photosensitivity, making unprotected skin cells more vulnerable to UV damage. Even minimal amounts of exposure can cause real harm.

A small amount of time in the sun can leave a lupus patient with a severe, sunburn-like rash, painful blisters, and skin swelling. And while this reaction begins in the skin, it can trigger a more intense lupus flare-up throughout the body, causing joint pain, fever, and extreme fatigue.

Stay indoors during the parts of the day when the sun is brightest and protect your skin as much as possible with the right clothing and plenty of sunscreen.


Asthma symptoms, like those of many respiratory illnesses, can be brought on or worsened by extreme heat during the summer months. High temperatures and humidity cause the air to not move as much, which can trap pollutants in the airways and lead to an asthma attack.

The air is also generally poorer quality during the summer months, particularly in highly populated cities or areas affected by wildfires. High winds caused by summer thunderstorms can also lead to asthma flare-ups by circulating mold, spores, and pollen.

One way to beat these conditions is to stay indoors as much as possible, especially if you’re exercising.


Too much sunlight can easily irritate the skin of people who have rosacea, causing flare-ups of redness and bumps in the complexion, especially around the nose and cheeks. Excessive heat can dehydrate the skin, making these symptoms even worse.

To minimize the chances of these flare-ups, be mindful of how much time you’re spending in the sun and take proper precautions to avoid too much exposure or overheating.

Take note of certain medications, too

It’s not just medical conditions that are impacted by the arrival of summer. Side effects of certain medications can also worsen due to heat and sun.

Medications that increase the skin’s sensitivity to sun can make a sunburn much worse than it would be otherwise. There are many medications that fall into this category — including antifungals, oral contraceptives, and some antibiotics — so ask your pharmacist if you’re just starting to take something new.

Other medications, such as those for migraines or allergies, reduce sweating. This makes it more difficult for the body to respond in the right way when it’s getting overheated. You should consult with your doctor or pharmacist about this possibility, if you’re concerned.

But we don’t want you to start singing the summertime blues just yet. You can still enjoy the season if you have any of these conditions. You just need to be aware of the extra steps you should take to ensure your health isn’t at risk.

If you’re unsure how your treatments might be impacted by the sun or heat, our pharmacists are available 24/7 to answer all your questions.

Posted date: June 14, 2022

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