Dear Doctor: Recently, my skin became irritated and started blistering. I was diagnosed with lichen planus, which I’m told is pretty common. What is it? How can people deal with the irritation and itchiness it causes?

Dear Reader: Lichen planus is a condition in which swelling, irritation and inflammation develop on various areas of the body. You’re correct that it’s common. And although lichen planus is most often seen on the skin, as in your case, it can also occur on the scalp, nails and mucous membranes.

The specific symptoms depend on the area of the body that is affected. On the skin, lichen planus appears as flat, itchy bumps with a reddish or purple color. These are usually firm and sometimes quite shiny. When it appears on mucous membranes, such as the inside of the cheek, the gums, the tongue or the genitals, it presents with clusters of tiny white dots that can look like lace. These may be accompanied by sores or inflammation that is often painful. On the scalp, the condition sometimes results in hair loss. Individuals with lichen planus on the nails often see thinning or splitting, develop marked ridges or grooves, and may experience nail loss that can be temporary or sometimes permanent.

Although the specific causes of the condition are not yet known, it is suspected to be a disease of the immune system.

Diagnosis of lichen planus is typically done with a physical and visual exam of the affected area, and by taking a sample of skin or a sore to examine under a microscope. Because the symptoms can be similar to several other skin conditions, including eczema and psoriasis, a blood test may be used to further narrow down the diagnosis.

There is no cure for lichen planus at this time, so the focus is on managing the symptoms. This includes using antihistamines to alleviate itchiness, and topical corticosteroid creams or ointments to help with swelling and redness. Retin A and certain types of light therapy have been found to be useful in helping to clear up the skin. For some patients, the prescription ointments prescribed for eczema are helpful. And in severe cases of lichen planus in which a patient has large areas of sores or bumps or experiences extreme itchiness or pain, corticosteroids such as prednisone, delivered as a pill or an injection, can provide relief.

When the condition develops in the mucous membranes, such as inside the mouth or on the genitals, the moist and enclosed environments make treatment more challenging. In the genitals, it can cause enough pain to interfere with sex. Sores in the mouth can make eating more difficult. Lichen planus also increases the risk of gum disease, which makes dental hygiene, including professional teeth cleaning, vital.

The good news is that the condition will often go away on its own over the course of a year or two. However, about 20% of people experience a recurrence. It’s not contagious, but there is evidence that some forms of lichen planus can run in families. Since people living with hepatitis C often also develop lichen planus, researchers are now exploring possible connections between the two.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: How bad are cleaning products for our lungs? My mom keeps talking about a news story that said chemicals in cleaning products are as dangerous as cigarettes. Is my clean kitchen killing me?

Dear Reader: Your mom is referring to the results of a study published last year that found that not only do cleaning products harm the respiratory system, they seem to adversely affect women more than men.

The study, conducted by researchers from the University of Bergen in Norway, assessed the lung health of more than 6,200 women and men over the course of two decades. Among the information the participants were asked to provide was how often they cleaned with chemical products, how much of each product they used, and whether or not they were professional house cleaners. Lung function was regularly assessed, including by measuring the volume of air each person could forcibly breathe out in a single exhale. When the data was analyzed, researchers found that cleaning with chemical products as little as once a week resulted in an increased risk of decline in lung function. More frequent use of chemicals came with a greater risk of decline. The researchers said using cleaning products for 20 years had the same adverse effects on the lungs as smoking 20 cigarettes a day for two decades.

Interestingly, although men who used cleaning products and worked as professional cleaners also experienced a decline in lung function, it was less severe than the effects seen in women.

Previous studies have identified a link between the chemicals in household cleaners and respiratory conditions like asthma, headache, migraine and allergies. This is believed to be due to the caustic agents in the products, such as bleach, ammonia and other volatile organic compounds (VOCs). These can irritate and even injure the sensitive mucosal linings of the respiratory tract. Over time, this may lead to persistent changes at the cellular level that adversely affect lung function. Also at issue are the delivery methods of cleaning products, such as aerosol sprays. With a single push of the button, these can turn harsh chemicals into a mist of billions of easily breathable particles.

The authors of the study urged health officials to consider the strict regulation of cleaning products in order to protect consumers, and asked manufacturers to move away from aerosol products. Until that day, however, there are a few steps you can take at home to protect yourself. Consider wearing a dust mask or particulate filter while cleaning. These are widely available at hardware and home improvement stores, come in several types and styles, and are rated according to the substances that they filter.

No doubt you’ve heard it before, but never use cleaning products in an enclosed space. Open a window or door, or set up a fan to keep fresh air circulating.

Consider going old-school with soap and water, baking soda for scrubbing, and a water and vinegar solution for windows and mirrors. If you just can’t give up commercial products, visit epa.gov/saferchoice to find the safest ones.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)

Dear Doctor: Fracking just started near my Ohio hometown, and I remember reading about a connection to the risk of having a baby with low birth weight. I want to get pregnant, but now I’m worried. How close do you have to be to a site to be affected?

Dear Reader: "Fracking" is the common term for hydraulic fracturing, a drilling process that pumps fluid at ultra-high pressure deep into the earth. This fractures the underlying shale rock and makes the natural gas or oil that it contains available for extraction. There has been no end of controversy regarding the process in recent years, with vigorous debate over whether or not fracking causes air pollution, contaminates surface and groundwater, leads to earthquakes and plays a role in a range of health problems. Among the health questions that have been raised is whether the process affects birth weight among pregnant women who live near fracking sites.

Your question refers to a study published a few years ago in the journal Science Advances. The researchers, including one from UCLA, analyzed the outcomes of 1.1 million live births in Pennsylvania between 2004 and 2013. They compared the birth weights of infants born to mothers living at varying distances from active fracking sites, both before the extraction operations had begun, and after the wells became active. They found that women who lived very close to an active fracking operation -- within one-half mile -- had a 25 percent higher risk of delivering a baby of low birth weight than did women who lived at a distance of 2 miles or more.

The study found that babies born to women who lived more than one-half mile from a fracking site, but less than 2 miles away, were also adversely affected, but to a lesser degree. When researchers looked at women who lived at least 2 miles from a fracking operation, they found no signs of adverse health effects to newborns.

"Low birth weight" is the term used to describe an infant who weighs less than 5 pounds, 8 ounces at delivery. By contrast, the average healthy newborn weighs in at about 8 pounds. Low birth weight occurs most often in premature births, when the infant doesn’t have the full 37 weeks of gestation to grow and gain weight. Low birth weight is sometimes seen in full-term babies who failed to grow well during gestation due to issues with the mother’s health, the placenta or the baby’s condition. Multiple births also often result in smaller babies.

The reason low birth weight is a concern is that smaller babies are at greater risk of complications after delivery, including low oxygen levels, difficulty feeding, gastrointestinal problems and SIDS, or sudden infant death syndrome. Low birth weight has also been shown to be a risk factor for future health and developmental problems such as asthma, Type 2 diabetes, attention deficit disorder, learning disabilities and hyperactivity.

Although the study correlates proximity to fracking sites with low birth weight, it doesn’t explain what is causing these outcomes. The authors agree that more information is needed, and have said they hope their study will lead to further research.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10880 Wilshire Blvd., Suite 1450, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)