Do You Really Have Allergies?

Maybe, but you could actually have one of these annoying ailments.

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Your nose is irritated, you're run down, and you feel awful. About 40 million Americans have indoor and outdoor allergies—but are you actually one of them?

"Hay fever is so seasonal that people usually recognize it," says George Green, a Pennsylvania-based allergist and chief of staff emeritus of the allergy section of Abington Memorial Hospital. "Allergic patients usually talk more about sneezing, itching, and a runny nose." But some symptoms such as congestion and sinus pressure can be harder to pin down. If you've never been professionally evaluated, you may be using over-the-counter remedies inefficiently—or suffering for longer than you have to. Check out these common illnesses that can masquerade as allergies.

[See: Cold or Allergies? How to Tell the Difference]

Sinusitis. Fifty-one percent of adults said they misdiagnosed themselves as suffering from allergies when the cause was really sinusitis, found a 2011 survey from the Asthma and Allergy Foundation of America (AAFA). That's because congestion and facial pressure can signal an allergy or a sinus infection, says Linda Dahl, an otolaryngologist (a doctor specializing in the ears, nose, and throat) at Dahl Otolaryngology Center in New York City. Feeling consistently run down can also be a symptom of both health issues, says Lisa Liberatore, an otolaryngologist at New York City's Lexington ENT. How to tell the difference? One hint is the color of your mucus—icky but keep reading. Clear, liquid mucus often signals allergies, whereas yellow mucus tends to indicate infection, Liberatore says.

By the way, if you are diagnosed with a sinus infection, talk to your doctor about whether antibiotics are really needed. A study published in the Journal of the American Medical Association in 2012 found that antibiotics aren't always effective in treating sinusitis. Antibiotics treat bacterial infections—not viruses—and the "vast majority" of sinus infections are viral, according to new guidelines released by the Infectious Diseases Society of America. What's more, adds the group, over-treating patients with antibiotics can foster the development of antibiotic-resistant bacteria. Still, Liberatore, who tests her patients for bacteria, notes that antibiotics can be effective in some cases, as long as the correct antibiotic is prescribed. (She notes, for instance, that azithromycin and amoxicillin, the antibiotic used in the JAMA study, aren't the best choices for a sinus infection because bacteria may already be resistant to them.)

[See: What to Do for a Stuffy Nose]

Nonallergic rhinitis. Rhinitis simply means "irritation of the nose." But not all nasal irritation is triggered by allergies: It can be due to an overuse of nose sprays, hormonal changes, structural abnormalities of the nose (such as septal deviation), or sometimes medications, says the AAFA. Or your nose may be irritated by smoke, household cleaning products, or strong perfume, adds Liberatore. Symptoms can include a runny or stuffy nose and postnasal drip, and Green notes that some people feel worse when temperature or humidity levels change. If you're having chronic irritation, a specialist may first perform blood tests or skin tests to rule out allergies. Treatment for milder cases may include avoiding certain triggers, and serious cases may require prescription medication.

The common cold. It can be hard to know the difference between allergies and a cold (officially called infectious rhinitis), according to the AAFA. That's because the symptoms are so similar, and cold and seasonal allergies can become widespread at certain times of the year. You can ease cold-related congestion via nasal saline irrigation, sometimes done using a Neti Pot. "Sinus rinses are helpful in all cases," says Dahl, with "all cases" including sinusitis. Just follow safety instructions for Neti Pots; the Centers for Disease Control and Prevention recommends using distilled or sterilized water among other steps. And be careful with other nasal sprays and drops used to treat congestion, as they can cause "rebound swelling" if used for longer than three days, says the AAFA. That can end up making your short-term stuffiness a longer-term problem.