If you have allergies — to food, pets, pollen, mold or something else — or if you have asthma, borrow a lesson from the Boy Scouts: Be prepared — all the time.

According to the American Academy of Allergy, Asthma and Immunology (AAAAI), allergies affect as many as 40 million to 50 million people in the United States, triggering more than 8 million visits to office-based physicians each year. More than 17 million people, including 5 million children, have asthma.

Allergic reactions range from merely annoying — a friend's cat may trigger a bout of sneezing — to potentially deadly. According to the AAAAI, approximately 100 people in the United States die each year from food-related anaphylaxis and at least 40 die from reactions to insect stings.

Experts say the cardinal rule for allergy sufferers is to know what you're allergic to and to predict and avoid situations where you're likely to be exposed to those allergens. This is particularly important whenever you are away from home, whether you are visiting a friend or traveling abroad. Even if you are rarely affected by your allergies or asthma, you cannot always predict what reaction you might have in a new environment. Make sure you are armed with the medications you might need if you have a reaction.

People with food allergies, in particular, need to be on alert. There are numerous cases of people suffering a reaction to a food they thought was safe. U.S. Food and Drug Administration inspections have found bakeries using potential food allergens in products without listing those ingredients even when a business thought it was in compliance with food-labeling regulations. Therefore, you should assume that foods may contain trace amounts of unlabeled food allergens. You should be on special alert if you have an allergy to cow’s milk protein, peanuts, nuts, eggs, or wheat (gluten). Beginning in January 2006, the Food Allergen Labeling and Consumer Protection Act that was recently signed into law will require food manufacturers within the United States to clearly label their foods if they contain common allergy trigger ingredients. When there is not obvious labeling, it can be important to recognize your allergy trigger by alternative names: for example, cow’s milk may be included on an ingredient list under the name “casein” or “caseinate,” soy may be named “textured vegetable protein,” and eggs may be referred to as “albumin.” You should request a list from your doctor or allergist that shows foods to avoid for your allergy.

When traveling, you must be especially careful about the foods you eat that are prepared by others. If you have had serious, potentially life-threatening reactions to food in the past, especially if you have a peanut or nut allergy, make sure you take emergency medications with you when you go out to eat. To keep up to date with the latest alerts about unlabeled food allergens, check periodically with the Food Allergy and Anaphylaxis Network.

When you're on the go, you can take steps to make sure your travels don't become memorable for all the wrong reasons. The AAAAI offers these tips:

Having allergies does mean some extra work on your part to travel safely, but being aware of potential hazards and using an ounce of prevention can ensure you'll have an enjoyable and memorable trip for all the right reasons.