A relaxing dip in a hot tub may sound like the ideal way to spend a cool summer night. But in rare cases, danger may lurk beneath those soothing jets: Hot tub use has been linked with several types of infections and injuries. Here are five ways you can get hurt in a hot tub.
Hot tub lung
One unusual ailment linked to Jacuzzis is "hot tub lung," a lung disease caused by bacteria that can thrive in warm water. The bacteria, known as Mycobacterium avium complex (MAC), have a special outer layer that allows them to adhere to surfaces, rather than being washed away by water (as many other bacteria are). If a hot tub is contaminated with MAC, the bacteria can latch onto air bubbles and become aerosolized when the bubbles reach the surface, according to a 2017 paper on the condition.
When people breath in the bacteria, they may develop "granulomas," or small areas of inflammation, in their lungs. People with hot tub lung may experience flu-like symptoms, including cough, trouble breathing, fever and fatigue.
About 70 cases of hot tub lung have been reported in the medical literature, according to the 2017 paper. Most cases are tied to indoor hot tubs, where there is less ventilation. Most people see improvement in their symptoms when they simply stop going in hot tubs, but some people may need treatment with corticosteroids or antibiotics, according to a 2006 study from the Mayo Clinic.
Hot tub rash
If you break out in itchy spots after using a hot tub, you may have "hot tub rash." It's one of the more common illnesses linked to hot tubs, according to the Centers for Disease Control and Prevention (CDC). The rash is caused by an infection with the bacterium Pseudomonas aeruginosa, and symptoms include itchy skin that may turn into a bumpy red rash or pus-filled blisters surrounding hair follicles. The infection is often worse in the area under a person's swimsuit, because the suit may keep contaminated water in contact with the skin, the CDC says.
The risk of catching this type of infection in a hot tub is increased because the high water temperatures can cause disinfectants, such as chlorine, to break down faster, according to the CDC.
To prevent hot tub rash, the CDC recommends showering with soap and cleaning your swimsuit after getting out of the water. People can ask the hot tub operator if the disinfectant and pH levels are checked at least twice a day. The rash usually clears up without medical treatment.
Steamy hot tubs can also pose a risk of Legionnaires' disease, a type of pneumonia caused by Legionella bacteria. These bacteria are found naturally in water, and hot tubs that aren't disinfected properly can become contaminated with Legionella, according to the CDC. People become infected when they breathe in steam or mist from the contaminated tub, the CDC says. Making sure hot tubs have the right levels of disinfectants is essential to preventing Legionella infection, the agency says.
In very rare cases, getting into a hot tub can increase the risk of urinary tract infections (UTIs). The culprit in these infections is again Pseudomonas aeruginosa, which can cause UTIs. (This bacterium also causes hot tub rash.) In the 1980s, researchers in Denver reported three cases of UTIs linked to hot tub use. In all three cases, the patients developed UTIs within 48 hours of using the tubs. Tests showed the infections were caused by P. aeruginosa, which was also found in the tubs. It's possible that water jets could have propelled this organism into the patients' urethras, the researchers said.
In 2009, researchers in New York reported the case of a 38-year-old man who developed a potentially life-threatening condition called urosepsis after being in a hot tub. Urosepsis occurs when the bacteria that cause UTIs (in this case, P.aeruginosa) find their way into a person's bloodstream. The researchers identified the man's hot tub as the source of his infection. The patient reported having intercourse with his wife in the hot tub, which likely increased his risk of infection, the researchers said.
Still, this is uncommon. A 2000 study of risk factors for urinary tract infections among young women found no difference in use of hot tubs between those who had recurrent UTIs and those who did not.
Chemicals used to clean and disinfect hot tubs may cause allergic reactions in some people. In particular, a chemical called potassium peroxymonosulfate (PPMS), which is used to eliminate organic contaminates from the water (in a process called "oxidation"), has been linked with allergic reactions.
In 2010, a group of dermatologists in Ohio asked all of their patients with widespread rashes if they used hot tubs. Over the course of a year, they found six patients who were allergic to PPMS and who had also used this chemical to treat their hot tubs. All of the patients were men, and all of them saw improvement in their symptoms when they avoided hot tubs.
Original article on Live Science.