Seth Davies’ son Will was just a few months old when he had his first allergic reaction to baby formula containing whey or milk.

The Davies family later found out the list of no-nos for Will also included cheese, eggs, strawberries and tree nuts.

If Will eats any of those foods, the reaction can range from skin rashes and itching to difficulty breathing. Will, a 14-year-old student from Cumming at Greater Atlanta Christian School, carries an EpiPen, a device to treat allergic reactions, everywhere he goes. His mother keeps one in her purse, and there’s always one in the car.

“We try to let him live a normal life, but he has to read labels, and there are very few times he can eat in a restaurant,” said Seth Davies, managing partner in an Alpharetta consulting firm. “The reality is you can’t let your guard down.”

Recent incidents, such as the death of Jharell Dillard, underscore just how cautious people with food allergies have to be.

Jharell, 15, died last week after eating chocolate chip cookies that contained peanuts. Another student, Tyler Cody Davis of Marietta, died after a call was placed to 911 from Kennesaw State University. An autopsy report has not been released, but a note posted on the soccer website of Sprayberry High School, where Davis was a 2009 graduate, said he died of an allergic reaction.

“It’s a lack of awareness and education about food allergies that is leading to these tragic events,” said Dr. Jon Stahlman, an allergy specialist and president of the Georgia Allergy Society. “These are things that are preventable.”

Simply put, Stahlman said, an allergy causes the body to overreact to a common food or substance by releasing a series of chemicals into the body, the most common being histamine.

“This creates a cascade of events that can affect any system adversely in the body,” he said. “For example, it can cause rashes and swelling of the skin, it can cause spasms and swelling of the airways and cause the cardiovascular system to collapse.”

The Food Allergy and Anaphylaxis Network says most allergies are caused eight foods: eggs, fish, milk, peanuts, shellfish, soy, tree nuts and wheat.

And experts say allergies are becoming more common.

Stahlman said about 3 million children younger than 18 have reported some form of food allergy, and the incident of allergies increased 18 percent between 1997 and 2007.

“It’s important for patients to work with their doctors to determine whether they are experiencing a food allergy or food intolerance,” Stahlman said. “Allergies are due to the immune system overreacting, whereas intolerance can involve many different things such as the inability to digest certain proteins, such as lactose intolerance.”

Dr. Stanley Fineman, an allergist with the Atlanta Allergy & Asthma Clinic, said teens are at particular risk because “they don’t, as a group, carry their epinephrine injectors.”

He said some people can outgrow certain food allergies, and other allergies can develop later in life.

Most school districts have policies in place to ensure students’ safety.

Susan Hale, a spokeswoman for Fulton County Schools, said schools develop “care plans” with parents and doctors so students’ allergy concerns are identified. Food allergies and treatment options are detailed in one plan while dietary concerns are addressed in another. Forms are shared with the clinic assistant and the cafeteria manager so changes can be made to meals and so they can be double-checked before being served.

Will Davies leads a life almost typical of young teens.

He’s active in sports and enjoys hanging out with friends. But when friends go to restaurants, Will will drink and wait until he gets home to eat. When he goes to a restaurant with his family, he makes sure the chef knows about his allergies. He feels safe eating at McDonald’s and Wendy’s.

His last allergic reaction happened this year when he joined his family at a Mexican restaurant.

“I think we got too comfortable eating out at places,” Will said. He ate some tortilla chips and felt fine for a while. Later, he began to develop welts and his tongue started to itch. He suspects the restaurant cooked the chips in the same oil it used for fish or may have used peanut oil.

Country singer-songwriter Luke Pilgrim, 24, of Cleveland carries two EpiPens, an inhaler and Benadryl at all times for a peanut allergy.

“I have to check what I eat,” he said, “and usually the people I surround myself with are aware of the allergies.”

He had a close call a few years ago. For a high school graduation party, his sister made an ice cream cake, one she had made several times before.

This time, though, she used a different ingredient not knowing that it contained traces of nuts.

Before he finished the first bite he went into anaphylactic shock. His throat began to itch, and he felt a severe pain in his chest. His lungs started to collapse. His family quickly used Benadryl and an EpiPen and called 911. But the ambulance had trouble finding their location, so a friend jumped on his motorcycle to find it.

“I was just praying,” Pilgrim said. “I thought this was the end for sure. You’re so scared. You’re hyperventilating and blacking out. I’ve heard people get a sense of impending doom.”

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FOOD ALLERGY TIPS AND RESOURCES

Take action

These severe symptoms require a shot of epinephrine or a trip to the hospital:

-- Shortness of breath, wheezing, repetitive coughing

-- Weak pulse, dizziness, confusion

-- Tight throat, hoarseness, trouble breathing or swallowing

-- Swollen tongue and/or lips

-- Hives, itchy rashes

-- Vomiting, cramping

Managing food allergies

Always carry your medications. Many people with allergies carry an epinephrine autoinjector (EpiPen, EpiPen Jr., Twinject). This device injects a single dose of medication when pressed against the thigh.

Action plan

Create a food allergy action plan with your allergy specialist. A sample action plan is available at foodallergy.com.

-- Educate family members, teachers, caretakers and friends about your food allergy. If you have been prescribed epinephrine, make sure the people closest to you know how to administer the drug.

-- Replace epinephrine before its expiration date.

Treatment

When to give over-the-counter or prescribed antihistamine (mild symptoms):

-- Itchy mouth, few hives, mild itch

-- Mild nausea

Resources

-- Food Allergy Kids of Atlanta: www.foodallergy kidsatl.org

-- The Food Allergy & Anaphylaxis Network: Foodallergy.org.

-- Allergy and Asthma Center: www.allergyinatlanta.com

Sources: Dr. Jon Stahlman, Allergy and Asthma Center in Atlanta, Lawrenceville and Conyers; the Food Allergy & Anaphylaxis Network; the Mayo Clinic