Beuatery

Melasma is a pigmentation disorder of the skin mostly affecting women, especially those with darker skin. It is commonly seen on the face, and appears as dark spots and patches with irregular borders. Melasma is not physically harmful, but studies have shown that it can lead to psychological problems and poorer quality of life due to the changes it causes in a person’s appearance.

Melasma is a common disorder, with a prevalence of 1% that can increase to 50% in higher-risk groups, including those with darker skin. Melasma is known as the “mask of pregnancy” since hormonal changes caused by pregnancy, as well as hormonal medications such as birth control pills, are major triggers for excessive skin pigment production in melasma. Sun exposure is another important contributor to melasma.

Can melasma be prevented?

Currently, melasma cannot be fully prevented in people who are likely to develop this condition due to their genetics, skin color type, hormones, or sun exposure level. Avoiding direct sun exposure during peak hours (10 a.m. to 4 p.m.), diligently using high-SPF sunscreens, and avoiding hormonal medications when possible may help protect against melasma flares and reduce their recurrence after treatment. Strict sun protection is the mainstay of any melasma treatment regimen.

What sunscreen should melasma patients use?

Choosing an appropriate sunscreen is critical if you develop melasma, and studies have shown that broad-spectrum tinted sunscreens, especially ones containing iron oxide, can lower pigment production in the skin in melasma patients, as they block visible light as well as UVA/UVB rays. Non-tinted sunscreens, on the other hand, do not block visible light.

For some people, it might be more convenient to use cosmetic products such as foundations that contain both UVA/UVB blockers and visible light blockers such as iron oxide. These products can conceal dark spots and therefore alleviate the psychosocial impact of melasma, and at the same time act as a sunscreen to protect against darkening of the lesions.

It is important for people with melasma to know that visible light can go through windows, and therefore even if they are not out in the sun, they can still get melasma flares by exposing themselves to visible light while driving or sitting by a window.

Can melasma be treated?

Currently there is no cure for melasma; however, there are several medications and procedures available to manage this condition. It is important to know that these treatment options may result in an incomplete response, meaning that some of the discolorations become lighter or disappear while some remain unchanged. In addition, frequent relapses are common.

It is also important to be aware of possible side effects of treatment, including darkening of the skin caused by inflammation induced by the treatment, or extra lightening of the skin in a treated area. Using the appropriate medications under the supervision of a dermatologist can help achieve treatment goals and maintain them with fewer relapses.

Common melasma treatments

The most commonly used treatments for melasma are skin lightening medications that are applied topically. These include medications such as hydroquinone, azelaic acid, kojic acid, niacinamide, cysteamine, rucinol, and tranexamic acid. These medications work by reducing pigment production and inflammation, and by reducing excess blood vessels in the skin that contribute to melasma.

Pregnant women (who constitute a big proportion of melasma patients) should avoid most of these medications except for azelaic acid, which is a safe choice during pregnancy. Hydroquinone is a commonly used skin lightener that should only be used for a limited time due to side effects that may happen with prolonged use. It can be used for up to six months for initial treatment and then occasionally if needed.

In most patients a combination therapy is needed for treatment for melasma. A common choice is the combination of hydroquinone with a retinoid that increases skin cell turnover and a steroid that decreases skin inflammation. Oral medications, including tranexamic acid, are usually considered in more severe melasma cases. This medication is thought to help melasma by reducing pigment production and by reducing excess blood vessels in the skin.

Additional treatment procedures may help

If your melasma does not improve with topical or oral medications, adding procedures such as chemical peels and laser therapies to a treatment regimen could be beneficial.

Chemical peels use substances like glycolic acid, alpha-hydroxy acids, and salicylic acid to remove the superficial layer of the skin that contains excess pigment in melasma patients. The effects of a chemical peel are temporary, since this procedure removes a layer of skin without reducing the production of pigment in regenerating deeper layers.

Laser therapies can destroy pigment cells in skin and therefore lighten the dark spots in melasma. However, as with any other treatment option for melasma, there is considerable risk of relapse post-treatment.

Maintenance therapy and prevention

After achieving improvement of melasma lesions, strict sun protection and maintenance therapy need to be continued. Skin lighteners other than hydroquinone can be used in combination with retinoids to maintain the results, and hydroquinone therapy may be used intermittently if needed.

Takeaway message about melasma

The key point in management of melasma is to use sun protection all the time, and to avoid other triggers such as hormonal medications when possible. Since none of the available treatments are a cure, prevention is the best option. People with melasma should see a board-certified dermatologist for evaluation and appropriate treatment regimens to manage melasma and maintain the treatment results.

About the Authors

Lilit Garibyan, MD, PhD, Contributor

Dr. Lilit Garibyan is an assistant professor of dermatology at Harvard Medical School, and a physician-scientist at the Wellman Center for Photomedicine at Massachusetts General Hospital. Her research focuses on innovative biomedical discoveries aimed at identifying … See Full Bio View all posts by Lilit Garibyan, MD, PhD

Sara Moradi Tuchayi, MD, MPH, Contributor

Dr. Sara Moradi Tuchayi is a dermatology research fellow at Massachusetts General Hospital. Her research at the Wellman Center for Photomedicine at MGH is focused on the development of novel therapies for skin disorders. See Full Bio View all posts by Sara Moradi Tuchayi, MD, MPH

Many people seek medical attention when they have diarrhea, usually when it is severe or is not improving. Doctors like myself ask questions to see what could be causing the problem: Food poisoning? Irritable bowel syndrome? Medication side effects? We also consider that diarrhea may be due to Clostridioides difficile infection (CDI).

What is C. diff infection?

CDI is a bacterial infection that can cause severe problems in the gastrointestinal tract, especially the colon. C. diff is responsible for almost half a million infections in the US each year, and it can be a recurring problem: one in six patients with this infection will get it again within two months. Sadly, one in 11 patients over age 65 who is hospitalized for CDI will die within one month of infection due to the severity of illness in CDI. Therefore, CDI is an important public health consideration, and it’s important to get treatment.

Who at risk for C. diff infection?

There are certain risk factors for developing a CDI. These include being hospitalized, having been exposed to antibiotics, or having close contact with someone who has been diagnosed with the infection. If you are immunocompromised (have a weakened immune system), you may be also at higher risk of contracting CDI or of suffering a complication from it.

A major focus of reducing the burden of CDI in the healthcare system is trying to reduce the risk of getting CDI in the hospital. This includes testing for CDI in hospitalized patients who develop new diarrhea, and then isolating those patients into their own rooms.

Prevention also includes washing your hands thoroughly with soap and water. This is a particularly important point because in healthcare settings, alcohol-based sanitizer often is used for convenience when clinicians practice preventive infection control between caring for patients. Alcohol-based sanitizer is not effective against CDI as it is for other types of infection because, unlike other bacteria, C. diff organisms can form resistant spores.

So, to protect yourself in health care settings, you should make sure the people who interact with you — doctors, nurses, medical assistants, etc. — have washed their hands prior to touching you. It can seem rude to ask someone if they have washed their hands. However, all people who work with patients receive training about hand-washing, and sometimes we simply forget in the middle of busy days, so it can be helpful to remind us.

What about CDI transmission outside of medical settings?

What is less understood is when CDI happens outside the hospital. A recent article in Emerging Infectious Diseases reported the presence of CDI in patients who became infected in a way that doctors tend not to think of as often: getting CDI from someone they know without ever being hospitalized or taking antibiotics themselves.

As physicians, we are drilled on the factors previously mentioned — prior use of antibiotics, previous hospitalization — as critical events that may cause CDI. What this research demonstrated is that people without these risk factors developed CDI by being exposed to someone with CDI in the community. It turns out that this is a common way people end up contracting CDI. During my training, we learned that it is important to remind patients newly diagnosed with CDI to be mindful of good hand hygiene, and to avoid as many contacts as possible until their CDI treatments were completed. This new research suggests that focusing on community CDI transmission should be a greater priority.

How is CDI treated?

The first round of CDI treatment is usually antibiotics (ironic, since antibiotics can cause CDI). These include metronidazole, vancomycin (in oral form only), and fidaxomicin. Every few years guidelines are reviewed and updated, but generally, different antibiotic treatment courses are given based on CDI illness severity, whether there is an infection that is failing to clear, or if a new antibiotic needs to be tried.

A promising way to treat CDI, particularly in patients who have not been helped by antibiotic therapy, is to give a fecal microbiota transplant, or FMT. This treatment involves taking a healthy person’s stool donation and administering it during an endoscopy procedure by mouth, during a colonoscopy, or in frozen form by pill. I know — taking someone else’s poop sounds so icky! However, the purpose is to introduce healthy bacteria into a gut that is sick with CDI, and the theory is that these healthy bacteria expand and make the environment harder for the C. diff bacteria to live and cause problems.

What precautions help prevent spread ofCDI?

The rules are simple for reducing your risk of CDI. If you have a weakened immune system, stay away from people who have been diagnosed with CDI. Thoroughly wash your hands with soap and water (not disinfectant) to deal with C. diff spores more effectively. When you are sick, take antibiotics only if they are necessary; doctors often feel pressured to write antibiotic prescriptions for people who have viral illnesses (for which antibiotics do not work).

Evidence is not strong for taking probiotics or eating yogurt to prevent CDI, but these approaches are low-risk ways to introduce healthy bacteria into your gut; this may be reasonable, in part because some in the medical field continue to debate their effectiveness.

Bottom line: if you are having diarrhea that just won’t go away, talk to your doctor to see if you have CDI or if there is something else causing your symptoms.

About the Author

Christopher D. Vélez, MD, Contributor

Dr. Christopher Vélez is an attending gastroenterologist in the Center for Neurointestinal Health of Massachusetts General Hospital's division of gastroenterology and the MGH department of medicine. He focuses on neurogastroenterology and motility disorders of the esophagus, … See Full Bio View all posts by Christopher D. Vélez, MD

Polio is a potentially life-threatening or disabling illness that spreads from person to person. Thanks to vaccination, the United States has been polio-free since 1979, and the spread of this highly contagious disease has been interrupted in most countries. Yet on June 22, the United Kingdom Health Security Agency announced that it had detected poliovirus in a most unexpected place: the sewers of London.

Over the past several months, scientists at the agency repeatedly found poliovirus in London sewer water. The viruses were genetically similar, suggesting that they were the result of limited spread within a family or close-knit community. Just how concerned should all of us be about this news?

Health clues found in wastewater

Sampling of wastewater for genetic material from viruses is a powerful tool used by epidemiologists to track outbreaks of polio and other diseases. Surges in the amount of SARS-CoV-2 RNA in Boston wastewater have been highly predictive of COVID outbreaks. Wastewater may also help to detect the spread of influenza and antibiotic-resistant bacteria.

Poliovirus infection was once a common and dreaded disease. Most people with poliovirus either had no symptoms or mild gastroenteritis (stomach flu). But one in 100 people developed paralysis, or poliomyelitis. In half of the affected patients, this paralysis was permanent.

In the UK, wild poliovirus has been eliminated since 1984. Although great progress has been made in many parts of the world, complete eradication of polio has been elusive. Pakistan and Afghanistan have never been free from wild-type polio, and outbreaks have recently taken place in Malawi and Mozambique, countries which had previously eliminated polio.

The reasons for this backsliding are complex. Some contributing factors are diversion of scarce resources toward the COVID-19 pandemic, backlogs in vaccine manufacturing, anti-vaccine agitation, and violence directed at vaccine workers.

Another problem is vaccine-derived poliovirus. In the United States and most other countries, injections containing killed viruses are used. While these vaccines are safe, they are less effective than oral vaccines at breaking the chain of polio transmission. Oral vaccines stimulate long-lived immune responses in the lining of the intestines, where polioviruses replicate. Unfortunately, oral vaccines contain weakened but live viruses, which occasionally revert to a more dangerous form. In fact, the poliovirus found in London was a vaccine-derived strain that the infected individual had likely acquired from travel abroad.

Who is at risk for poliovirus stemming from this source?

Vaccine-derived viruses pose little risk to highly vaccinated populations, but they are able to spread in communities with low polio vaccination rates. In some cases, this can even cause paralytic disease. Because of these risks, steps are being taken to gradually phase out the use of oral polio vaccines.

If you’re concerned about polio, the best protection against this disease is vaccination. Children should receive a full series of four shots of inactivated polio vaccine, given at specific intervals, that helps with developing immunity.

Nationwide, rates of childhood polio vaccination in the United States are still high (nearly 93%). However, some infectious disease experts worry that the weakening of vaccine mandates in some areas has created islands of vulnerability in this sea of immunity. Communities in the US with low childhood vaccination rates have been vulnerable to large measles outbreaks in recent years, and might also be vulnerable to polio outbreaks.

With few exceptions, adults who were fully vaccinated as kids do not need booster shots. These exceptions include travel to a country with active polio transmission, laboratory work with poliovirus, or providing health care to polio patients and their close contacts. A single lifetime booster dose of inactivated polio vaccine is adequate for these high-risk scenarios.

About the Author

John Ross, MD, FIDSA, Contributor

Dr. John Ross is an assistant professor of medicine at Harvard Medical School. He is board certified in internal medicine and infectious diseases, and practices hospital medicine at Brigham and Women’s Hospital. He is the author … See Full Bio View all posts by John Ross, MD, FIDSA