As face masks become an indispensable part of life during the coronavirus pandemic, many people are confronting an uncomfortable fact: prolonged use can give rise to skin trouble. And as summer comes, the problem may get worse.

According to several clinics and a hospital in Tokyo, an increasing number of patients have been complaining of inflamed skin and other issues of sensitivity to masks, such as cuts behind the ears from the masks' elastic bands.

People wearing face masks amid coronavirus concerns walk near JR Tokyo Station under the strong sun on June 15, 2020, with the mercury topping 30 C in the capital. (Kyodo)

"As the humidity and temperature rise, the skin's condition inside the mask worsens. It gets damaged because of the friction between the mask and the skin," said Kotaro Yoshitake, the head of a dermatology and plastic surgery clinic in Tokyo.

In June, Kotaro Clinic recorded its highest-ever number of patients, boosted by sufferers from mask-related skin problems, with such complaints tripling compared to the same month the previous year.

Yoshitake, 35, puts the patients' skin trouble into two categories -- skin inflammation and acne.

"One of the worst cases was when the back of one of my patient's ears was cut on the top and bottom because of the friction of elastic bands on the mask," he said.

Kotaro Yoshitake, head of Kotaro Clinic, speaks during an interview in Tokyo on July 1, 2020. (Kyodo)

Unlike a number of countries and regions, Japan has not mandated by law the use of masks in public, but there is strong social pressure to do so, with some who fail to don them complaining of harassment under the Twitter hashtag #maskpolice.

And that means wearing a mask has become a part of daily life for most people as social interactions increase again following the government's lifting in late May of its state of emergency and scaling back of stay-at-home and business suspension requests over the pandemic.

YouGov, a British polling firm, found that 86 percent of Japanese surveyed in early May wore masks in public spaces. That compares with 82 percent in China and 71 percent in the United States as of June 22. The rate in Germany was 64 percent as of June 18 and in the United Kingdom 31 percent as of June 25.

But for some, the discomfort is unbearable.

"If people have skin problems and care what other people think of them not wearing a mask, using hand-made cloth masks are an alternative. They are gentle on your skin and have the same infection prevention rate as the non-woven masks sold at pharmacies," Yoshitake said.

And while Yoshitake recognizes the importance of wearing a mask in public as it can prevent people from dispersing large droplets of saliva containing the virus, he says it is not necessary for sufferers to wear one if they take other safety steps.

Yuta Nishimura, managing director of Galleria International Co., shows how to wear a plastic head band for face masks in Tokyo on June 26, 2020. (Kyodo)

"If you have facial inflammation, then if you don't cough and can maintain distance with other people, it is not absolutely mandatory to wear a mask even if you are in an office at work," he said.

Kaoru Takayama, an associate professor at Tokyo Medical and Dental University, also suggests lessening the time spent wearing masks when skin trouble is an issue. "Perspiring (inside a mask) and leaving it on can cause dryness and skin irritation," Takayama said.

Like Yoshitake's clinic, the university's affiliated hospital is seeing patients with inflamed cheeks and acne due to face masks.

"To prevent such inflammation, moisturizing your skin and using masks that are gentle to your skin is important," Takayama said.

"The non-woven fabric masks are not stretchy, and if not worn properly, the mask will rub against the skin when people talk," Takayama said.

Yoshitake also warns that using non-woven fabric masks, which most people use, may damage the skin, as the coating chemical is unknown. "It may include chemicals that can cause allergic reactions."

"Another tip is to put tissues or cotton in between the face and the mask. It can prevent direct friction that causes the skin trouble," he said. "The premise of the preventative measures is to choose a mask that fits your face. Wearing small masks is terrible for your skin."

To alleviate symptoms after patients get rashes, Yoshitake and Takayama suggest moisturizing the inflamed area and rubbing prescribed steroids into the skin.

Yoshitake said that dermatologists would usually prescribe antihistamines whenever patients have allergic reactions due to the masks.

As the summer gets into full swing, with more intense sunlight and higher temperatures, there will be more causes of skin trouble, he warned.

"Ultraviolet rays could weaken the face skin barrier, which could lead to more trouble," he said. "Putting on sunscreen will become essential in the coming season."

Some companies, meanwhile, have started to provide a solution for people who get pain behind their ears.

Yuta Nishimura, managing director of Galleria International Co., shows how to wear silicon band ear guards for face masks in Tokyo on June 26, 2020. (Kyodo)

Galleria International Co. in Tokyo's Shibuya Ward, which usually sells smartphone cases and concert goods, has utilized its know-how in plastic processing to offer two products to alleviate sore ears.

The silicon band ear guard protects behind people's ears as it prevents the mask's elastic band from direct contact with the skin.

Another product, the plastic mask band, is also designed to avoid direct contact as it connects behind people's heads rather than hooking to their ears.

"Our company has sold 10,000 (of the guards and plastic mask bands) each in Japan since we put them on the market June 1. Our products, such as smartphone cases, usually sell only a maximum of around several hundred," said Yuta Nishimura, 38, the company's managing director.

Before the launch in Japan, the company sold around 500,000 ear guards and plastic mask bands each in China, where it has a factory.

The company has received numerous positive messages from customers saying, the goods "saved them from pain."

"We are planning to produce more as there seems to be a higher demand for these products," Nishimura said.

"If the size of the mask fits a person, I think the goods may have positive effects to prevent such pain," Tokyo Medical's Takayama said. "However, we have to keep in mind that one cause of skin inflammation is the mask's pressure on a person's face."

The company has now started to offer a "cold mask," which relieves heat inside the mask. With more than 350,000 sold, the mask is one of the company's biggest hits.

The company also sells a mask that not only cools but can also cut ultraviolet rays. It forms a curtain covering the nose, mouth and front part of the neck.