Smoking has been proven to be extremely harmful to the respiratory system. For people with asthma, tobacco smoke frequently tops the list of the most common triggers of an asthma attack. An asthmatic does not have to smoke to be affected, as even second-hand smoke can trigger asthma attacks or cause permanent harm to the airways, making it easier to have an asthma attack in the future.

Tobacco smoke is usually inhaled from a cigarette, cigar or pipe, and a number of chemicals in tobacco smoke have been proven to harm the lungs, as well as the arteries and other parts of the body. Asthmatic children are the most susceptible to tobacco smoke – particularly second-hand smoke. Children have smaller airways, so the airway constriction and mucus buildup that occurs after inhaling tobacco smoke can cause a severe asthma attack in a child. Children should avoid people or situations in which smoking is common.

Anyone with an asthmatic condition who smokes should immediately quit. Smoking can greatly complicate an asthmatic condition by damaging the lungs, even if it does not trigger an attack. In addition, many health risks have been linked to smoking, including cancer, respiratory infections and types of heart disease.

For a multitude of reasons, expectant mothers should not smoke. Low-birth weight and a host of medical problems have been linked to smoking. For instance, children born to mothers who smoked while pregnant are 10 times more likely to develop asthma.

More than 17 million people suffer from asthma in the United States according to the American Academy of Allergy, Asthma and Immunology. Many list tobacco smoke as one of their most common triggers of asthma attacks.

Tobacco is usually smoked through one of the following:

• Cigarette
• Cigar
• Pipe

Roughly 200 of the 4,000 chemicals in tobacco smoke are considered toxic, and about 40 of the chemicals are known carcinogens (substances which are capable of causing cancer). Several of these harmful chemicals can directly trigger an asthmatic attack or increase the likelihood of an asthmatic attack occurring. These include:

• Ammonia. Can irritate the lungs when inhaled.
  
  
• Methanol. Considered toxic when inhaled or swallowed.
  
  
• Hydrogen cyanide. Causes an interference with normal respiratory function.
  
  
• Carbon monoxide. Lowers the amount of oxygen in the blood, which hampers breathing.
  
  
• Tar. Leaves a residue on the interior of the lungs, lowering lung function.

Tobacco smoke is one of the most commonly acknowledged asthma triggers. It is capable of entering the lungs in two forms: direct inhalation and second-hand smoke. Although both are very harmful, second-hand smoke can, in some circumstances, be more dangerous because it contains higher concentrations of damaging substances, such as tar and carbon monoxide.

In either form, once tobacco smoke has been inhaled, it can cause an asthma attack by settling on and irritating the smooth muscles that surround the airways, causing them to constrict. This closes off the airways, potentially causing shortness of breath or difficulty breathing.

In addition, tobacco smoke may cause the mucous membranes that line the airways to produce greater amounts of mucus than normal. Excessive mucus diminishes the diameter of the airway, reducing the amount of air that can be brought into the lungs and inhibiting normal respiration. This mucous membrane reaction alone can bring on an asthma attack in many individuals. It can also worsen attacks already in progress.

Tobacco smoke also damages the cilia that line the airways. These tiny, hair-like structures are an important mechanism for the removal of dust and excess mucus from the airways. These secretions also offer a favorable spot for infections to begin, which can further clog an already inflamed airway.

Directly inhaled smoke and second-hand smoke can cause a person to experience asthma attacks more frequently. These attacks may also be more severe. In addition, tobacco smoke can make asthma attacks harder to control with medication, by undoing the effects of controller medications and increasing the need for rescue medication. Ultimately, this may lead to more visits to the physician or the emergency room. Directly inhaled smoke and second-hand smoke can also cause death.

All types of tobacco smoke are extremely harmful to a person with asthma. There are generally two different ways an individual can come into contact with tobacco smoke:

• Directly inhaled smoke. Sucking on the end of a cigarette, cigar or pipe and pulling tobacco smoke directly into the lungs. The smooth muscle that surrounds the airways in a person with asthma is very sensitive. Exposing this muscle to the numerous chemicals found in tobacco smoke (e.g., ammonia, hydrogen cyanide) can cause an immediate asthma attack as the muscle squeezes down and obstructs the airway.
  
  
• Second-hand smoke. Also known as passive smoke, this type is generally inhaled by people in the same room or area as a smoker. It includes:
  
  
• Sidestream smoke. Type of smoke produced from the burning material itself, and not directly inhaled and exhaled by the smoker.
  
  
• Mainstream smoke. Smoke directly inhaled by the smoker (through a cigarette, cigar or pipe) and then expelled out into the air.

While inhaling second-hand smoke may seem less harmful than actually smoking, it is actually more harmful. This is because second-hand smoke contains higher concentrations of many harmful substances, including twice the amount of tar and nicotine and three times the amount of carbon monoxide.

Even though wood smoke contains far less of the dangerous chemicals associated with tobacco smoke, asthma sufferers should also try to stay away from wood burning stoves and fireplaces. Studies have demonstrated that wood smoke can cause an increase in respiratory symptoms, lowered respiratory function and lowered pulmonary function.

Smoke from candles and incense may also exacerbate the respiratory conditions of a person with asthma. The U.S. Environmental Protection Agency (EPA) advises individuals with asthma to remove candles and incense from the home.

Tobacco smoke can cause a wide range of medical conditions. While these conditions pose health risks on their own, many can also greatly complicate an asthma condition. These conditions include:

• Allergies. Exaggerated reaction of the immune system to harmless substances to which people are sensitive. Tobacco smoke can worsen the symptoms of an allergy by exacerbating a person’s respiratory condition.
  
  
• Bronchitis. Inflammation of the mucous membranes in the bronchial tubes. Children are susceptible to developing this condition from second-hand tobacco smoke.
  
  
• Pneumonia. Inflammation of the lungs. Children with asthma are much more likely to develop this condition when in regular contact with second-hand tobacco smoke.
  
  
• Middle ear conditions (e.g., otitis media). Ear infection or buildup of fluid in the ears. This condition is commonly experienced by children who live in homes with smokers.
  
  
• Cancer. Growth or tumor caused by the abnormal or uncontrolled growth of cells in the body. The U.S. Environmental Protection Agency (EPA) has classified second-hand tobacco smoke in the most dangerous cancer-causing category.
  
  
• Ischemic heart disease. Condition characterized by the narrowing of the blood vessels leading to the heart. Second hand smoke damages blood vessels, limiting an individual’s activity and causing increased risk to the heart.
  
  
• Low birth weight. Abnormally low weight of a newborn infant. This condition has been directly linked to second–hand smoke.
  
  
• Sudden infant death syndrome (SIDS). Sudden and unexpected death of an apparently healthy baby while sleeping. Research indicates that the infants of mothers who smoke have twice the risk of SIDS.

While contact with smoke is a threat to anyone with asthma, it is especially dangerous for children. This is largely due to the fact that their lungs are still developing.

Children who spend the first few years of their lives in frequent contact with tobacco smoke are proven to be more likely to develop asthma. Young children in smoking households generally have more doctor visits, emergency room visits and hospitalizations than children who are not regularly exposed to secondhand smoke. Exposure to tobacco smoke can also increase the likelihood of an infant dying of SIDS (sudden infant death syndrome) and make a child more likely to develop respiratory illnesses (e.g., bronchitis, pneumonia) or an ear infection (e.g., otitis media).

Children with asthma are also likely to experience a worsening of symptoms after exposure to tobacco smoke. According to the American Academy of Allergy, Asthma and Immunology (AAAAI), up to one million children with asthma become more severe after exposure to second-hand smoke. In order to reduce the frequency of asthma attacks, asthmatic children should avoid all types of smoke as much as possible.

Tobacco smoke irritates the lungs and causes more mucus than usual to build up in the airways. Because children’s airways are smaller, even minor asthmatic blockages can have severe consequences for a child – particularly an infant or toddler.

In addition to the physical problems experienced by asthmatic children in smoking households, children who grow up around smokers are more likely to view smoking as acceptable and later smoke themselves.

Most physicians recommend that parents or guardians of children with asthma give up smoking completely. While this is considered difficult by many, a physician can help suggest some of the many programs and products currently available to help. Children with asthma should be raised with as little exposure to second-hand smoke as possible.

Parents of children with asthma should also make sure their child is not in contact with second-hand smoke at school, daycare or after-school activities. Restaurants and establishments that allow smoking should be avoided. Asthmatic children should also not ride in any vehicles with smokers. For more tips on what to avoid see, Preventing smoke exposure.

Pregnant women can pass many of the harmful chemicals found in tobacco smoke directly to their unborn children. Most physicians recommend that pregnant mothers immediately give up smoking and try to avoid second-hand smoke. Mothers who smoke during pregnancy are 10 times more likely to have a child who has asthma, and are much more likely to have a child with lung complications. Smoking during pregnancy also raises the chances of a child being born prematurely or with low weight.

Nursing mothers can pass along harmful chemicals to their babies if they smoke more than 20 cigarettes a day. Heavy smoking can also reduce the milk supply and cause symptoms in the nursing baby, including nausea, vomiting, abdominal cramps and diarrhea.

The most effective way to limit the negative effects of smoke on individuals with asthma is to avoid smoke – particularly tobacco smoke – as much as possible. Physicians recommend that asthmatics, as well as family members of asthmatics, follow these steps to limit exposure to tobacco smoke:

• Quit smoking
  
  
• Do not allow smoking in the home
  
  
• Do not allow smoking in the same vehicle
  
  
• Work with your employer to limit smoking at work
  
  
• Use the non-smoking areas at restaurants and other establishments, or avoid them completely

Smoking indoors near a window, holding a cigarette out a car window and smoking near a fan are not effective ways of limiting indoor second-hand smoke. Smoking in the presence of another person – anywhere or at any time – adversely affects the health of that individual, particularly if they suffer from asthma.

Some other types of smoke-producing sources should also be avoided. Wood burning stoves, candles and incense are all capable of producing smoke that can be harmful to a person with asthma.

In some areas, forest fires or brush fires can occasionally cause the local air to fill with smoke. While this type of air pollution will usually not severely harm a person’s lungs, it can aggravate asthma conditions. It is best for asthmatics to try to remain indoors until the air clears.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctors the following questions about smoking and asthma:

1. What effects does my smoking have on my/my child’s asthma?
   
   
2. What improvements will I see if I quit smoking?
   
   
3. How soon after quitting can I expect to see an improvement in my asthma?
   
   
4. Can you recommend a smoking cessation method?
   
   
5. What steps can I take to reduce contact with second-hand smoke?
   
   
6. Does tobacco smoke effect my allergies as well?
   
   
7. What other types of smoke can affect my asthma?