<p>Curious how allergy medicine works? The main active ingredient is antihistamines, which “work by reducing histamine levels in your body which is a chemical released by allergy (mast) cells in response to an allergen,” says Dr. Parikh.<br></p><p>This phenomenon causes allergy meds to work almost instantly. “Oral antihistamines can begin working 20 to 180 minutes after ingestion, while nasal steroids work best when used daily,” says Rabia Chaudhry, MD, an allergist and immunologist at South Florida Food Allergy Center. (You can take antihistamines daily, too, BTW.)</p><p>Some people even give allergies a one-two punch, but talk to your doctor before combining medications: “It’s not uncommon for a patient with severe allergies [to take] daily nasal steroids and oral antihistamines,” says Dr. Chaudhry.</p><p>One thing to note: If you’re having any breathing symptoms like coughing, wheezing, dyspnea, chest tightness, or any symptoms below the chest, do <em>not</em> treat this with an over-the-counter allergy medicine (including pseudofed and decongestants like oxymetazoline), Dr. Parikh says. Instead, seek medical attention because this could be asthma and symptoms such as these can be life threatening, she adds.</p><p><em>WH</em> narrowed down the best expert-approved OTC allergy medicines to choose from. </p><p class=”body-tip”><strong>Meet the experts:</strong> <br><br><a href=”https://clinicianresources.bcm.edu/people/profile/1468/” target=”_blank”>Evan Li, MD</a>, is an assistant professor of medicine, immunology, allergy, and rheumatology at the Baylor College of Medicine. <br><br><a href=”https://nyulangone.org/doctors/1629212592/purvi-s-parikh” target=”_blank”>Purvi Parikh, MD</a>, is an allergist with <a href=”https://allergyasthmanetwork.org/” target=”_blank”>Allergy & Asthma Network</a>. <br><br><a href=”https://southfloridafoodallergycenter.com/about/” target=”_blank”>Rabia Chaudhry, MD</a>, is an allergist and immunologist at <a href=”https://southfloridafoodallergycenter.com/” target=”_blank”>South Florida Food Allergy Center</a>.</p><p class=”body-text”> </p>” />