For most people, cold and flu season means suffering the temporary annoyances of a stuffy nose, a sore throat or a bad cough. But if you have asthma, the season poses a more serious threat than tissues and cough drops can handle.

"If you have asthma, there is a good chance that a cold or flu will trigger an attack," says James Li, M.D., a specialist in allergy, asthma and immunology at Mayo Clinic, Rochester, Minn. "Sometimes these attacks — which consist of increased shortness of breath, coughing and wheezing — are severe enough to require an emergency room visit or hospitalization."

You can take steps to lessen the likelihood of such an attack. Here's how.

The best way to avoid colds and the flu is to limit your exposure to them.

"Most of these viruses are transmitted by physical contact," says Dr. Li. "What you should do is limit your physical contact, wash your hands frequently, and regularly avoid contact with large crowds of people if you can."

Be sure to:

• Eat well. Enjoy a balanced diet, with plenty of fruits and vegetables.
• Get enough sleep. This will enable you to wake up feeling refreshed and alert.
• Exercise regularly. Aim for at least 30 minutes a day most days of the week.
• Minimize stress. Stress can interfere with your immune system's ability to fight disease.

If you have asthma, it's important that you get a flu shot every year. Although the flu vaccine can't prevent colds, it can be up to 90 percent effective in preventing the flu in healthy, young adults. Even when the vaccine doesn't prevent the illness, it's still effective at reducing the severity of the flu and helps prevent serious complications.

It takes about two weeks for the flu vaccine to take effect, so experts recommend that you get the shot in October or November — well ahead of the December-to-March peak influenza season. It's OK to be vaccinated in December or even later. The vaccination will still help ward off the virus through the rest of the flu season.

If you're in your first trimester of pregnancy, however, talk to your doctor before getting vaccinated. He or she might advise against it because it may put you at risk of complications.

If you're an adult with chronic asthma — especially an older adult — it's important that you get immunized against pneumonia (pneumococcal disease) as well, since the disease may occur as a complication of the flu.

Unfortunately, efforts to avoid viruses don't always work. So if you do get a cold or the flu, know when to seek medical attention.

"The earlier a cold and asthma attack are recognized and treated, the faster you'll get better," says Dr. Li. "It prevents severe attacks."

Recognizing the warning signs of an asthma attack is key to preventing a severe attack.

Warning signs in adults include:

• Increased shortness of breath or wheezing
• Sleep disturbed by shortness of breath or wheezing
• Increased use of bronchodilators
• A drop in peak flow rates

Warning signs in children include:

• Rapid breathing
• Abdominal muscles used when breathing
• Inability to complete sentences because of difficulty breathing
• Wheezing

Sometimes it can be difficult to detect the early signs of an attack. A peak flow meter can help you monitor your airflow.

"If you catch a cold and within a day or two you start to have chest symptoms like congestion, wheezing or shortness of breath, it's most likely the start of an asthma attack, and you should seek medical attention," says Dr. Li. "Ideally, you will already have discussed this scenario with your doctor so that you have a predetermined plan of action."

If you do have a cold or the flu and start to have an asthma attack, you'll likely need treatment. Treatment often includes:

• Short-term use of a corticosteroid, such as prednisone, which reduces the inflammation leading to swollen airways
• More frequent use of a rescue inhaler, such as albuterol (Proventil, Ventolin) or pirbuterol (Maxair)

When you have a cold or the flu and an asthma attack, antibiotics usually aren't needed. Antibiotics won't cure or relieve the symptoms of viruses. Unnecessarily taking an antibiotic can lead to bacteria that are resistant to the medication.

Figuring out whether you have something more serious than a cold or the flu can be tricky. Seek medical help if you have any of the following signs and symptoms:

• A severe sore throat
• A cough producing large amounts of green or yellow mucus
• Signs of pneumonia, such as a cough bringing up phlegm, a high fever and sharp pains when taking deep breaths

"It's sometimes difficult to know whether it is pneumonia, flu or cold," says Dr. Li. "If you have a high fever, shaking chills or sinusitis, you may need antibiotic treatment. When in doubt, contact your doctor."