You already know the telltale signs of sensitive skin: flushing redness, a stinging sensation and a taut “my skin is one size too small” feeling that flares when you apply a product your complexion rejects.Since the 1980s, the number of people who claim to have sensitive skin has doubled from 30 percent to about 60 percent of the population. Nearly everyone suffers from sensitive skin symptoms at some point in life—whether after a long trek in frigid winter air or after a microdermabrasion treatment at a spa.Yet experts say that incidences of clinically sensitive skin have not gone up. So what gives? While some people do have sensitive skin, others have sensitized skin, brought on by abusing their complexions with more irritating products and procedures than ever, along with environmental stressors. That adds up to what appears to be a sensitive skin epidemic.So how do you suss out whether you truly have sensitive skin or if you’ve sensitized your own skin? A look at the history of your skin’s behavior holds the key.“Sensitive skin is genetically inherited and is predominant in Caucasian skin of northern European decent,” says Annet King, director of global education for The International Dermal Institute and Dermalogica. “The skin is fairer, more reactive and the body has higher levels of histamine. If you have true, sensitive skin, this is how your skin has always been. This is how you were born.”Due to the higher levels of histamine, those with sensitive skin also tend to suffer from allergies, eczema and hayfever.MORE: The hows and whys of sensitive skinOn the flip side, sensitized skin can occur in any race at any age and is caused by overuse of products, travel, illness and environmental factors that weaken the protective layers of skin. A revealing sign that you have sensitized skin is if a cosmetic or skincare product that you use regularly suddenly begins to sting.Whether you have sensitive or sensitized skin, the triggers that exacerbate both conditions remain the same. Extreme hot or cold weather, dry air, stress, dehydration, caffeine and overuse of exfoliating skincare products all bring on the hallmarks of touchy skin— itchiness, redness and inflammation.But environmental and lifestyle factors aren’t the only culprit. Common ingredients found in skincare and cosmetic products could be entirely responsible for the phenomenon.“Sometimes medical treatments beget their own diseases,” says New York City plastic surgeon Michelle Copeland, M.D. “As many people use a wide array of skincare products on a daily basis, I see an increasing number of patients with reactions to chemical components used as vehicles, binders and sometimes active ingredients.”If you suspect that certain skincare products, such as retinols, glycolic and salicylic acids and sulfur, may be the cause of your easily upset skin, scale back or discontinue using them. Also, check ingredient labels to avoid products containing irritating dyes and fragrances. “It’s best to always use allergy-tested, fragrance-free products,” recommends Dr. Copeland. And lay off harsh scrubs and treatments like microdermabrasion, which can abrade the delicate barrier even further.MORE: Skincare for sensitive skinIf the sensitivity persists, stop using all products for a few days and then gradually reintroduce them one at a time to see if a specific one reveals itself as the problematic product.You’ll also want to be on the lookout for possible dietary triggers that make sensitive skin worse. Spicy foods that bring on redness and flushing, tannins found in red wine, eggs and gluten are all common catalysts.To kick off the healing process, focus on strengthening your skin. “The most important aspect is to get that barrier back intact as soon as possible to prevent irritants penetrating and causing inflammation,” advises King.Both sensitive and sensitized skin folks should look to products containing essential fatty acids to replace the lipid barrier, like gamma linoleic acid, phytosterols and ceramides. Eating sunflower seeds and avocados also help protect the integrity of skin by reducing water loss, adds King.Clinically sensitive skin types should also maintain a daily calming regimen, using skincare products that contain soothing ingredients like oatmeal, chamomile, ginger, aloe or cucumber treat sensitive skin. With some TLC, you’ll get the healthy, glowing complexion you crave.QUIZ: How Healthy is Your Skin?