There are so, so many ways — both internal and external, but all cursed — to end up with a patch of itchy skin. But once you’ve ruled out a mosquito bite, psoriasis and eczema are two of the skin concerns that probably come to mind. The conditions are extremely common — an estimated 10% of people in the U.S. will have some form of eczema in their lifetimes, and 3% have psoriasis — and have some of the same symptoms, which can lead to conflation in the consciousness of us non-dermatologists. Although psoriasis and eczema have some similarities, their typical appearances, common triggers, and potential treatments can vary.

Both psoriasis and eczema are chronic inflammatory skin conditions, says Dendy Engelman, MD, a board-certified dermatologist in New York City. But despite that same starting point, the two manifest differently. “Psoriasis is a result of an overactive immune system which leads to increased skin cell growth, causing large patches on the skin as result of the skin-cell build-up,” explains Dr. Engelman. “Eczema is also caused by an overactive immune system, but in this case, the skin barrier is weakened, therefore the moisture in the skin is depleted causing extra-dry and itchy skin.”

We spoke to dermatologists to get the low-down on the two conditions and how they differ. But even if these pros help you identify the source of that pressing itch (or red patch, or skin bump), keep in mind that a medical exam is the best way to determine what you’re dealing with. “Diagnosis by a healthcare professional is crucial for accurate treatment and management of these conditions,” says Divya Shokeen, M.D., a board-certified dermatologist in Manhattan Beach, California. While you’re waiting for that appointment, read on to educate yourself about the differences between psoriasis and eczema.

Meet the Experts:

• Dendy Engelman, MD, a board-certified dermatologist at Shafer Clinic in New York City.
• Blair Murphy-Rose, MD, a board-certified dermatologist at Laser & Skin Surgery Center in New York City and Southampton, New York.
• Divya Shokeen, MD, a board-certified dermatologist at Ocean Skin and Vein Institute in southern California.

In this story:

In short: probably not. Psoriasis manifests as patchy, red skin that often gets dry and cracked, says Dr. Shokeen. The affected areas are often covered with silvery scales, and even outside the affected area, patients “may also have thickened, pitted, or ridged nails.” You might also see red patches with eczema, but the area “often has brownish patches” with “small, raised bumps which could leak fluid and crust over when scratched,” Dr. Shokeen continues.

In addition, the location of the issue can provide a clue. Either concern can manifest anywhere on the body, but there are common areas where dermatologists often see issues. According to Dr. Engelman, eczema is more likely to develop in skin folds, such as in the creases of the arms or on the backs of the knees. In contrast, psoriasis is typically found “on the scalp, elbows, hands, knees, and face.” The way the affected area feels is also a major clue: The primary complaint for many eczema patients is itchiness, Dr. Engelman continues. But psoriasis can feel uncomfortable or sore, due to the cracked or bleeding skin.

Like heart disease, acne, insomnia, and pretty much every other medical condition, both psoriasis and eczema can be exacerbated by stress. But according to Blair Murphy-Rose, M.D., a board-certified dermatologist with offices in New York City and Southampton, New York, the list of triggers otherwise is different. For eczema, she lists allergies, exposure to skin irritants, and changes in weather and humidity. Psoriasis, meanwhile, can develop in “areas of trauma or friction,” and can be induced by some medications or even strep infections. A proper diagnosis is the first step toward learning which triggers to avoid, but thinking through your recent history may also help. If you just changed laundry detergents, for example, that may be a clue that you’re dealing with eczema; if you notice a skin plaque in the area of a recent scrape, psoriasis may be the culprit.

Treatment and prevention of psoriasis and eczema both involve increased awareness about how you take care of your skin. According to Dr. Murphy-Rose, those with eczema “tend to have dry skin and a diminished protective skin barrier.” That means that treatment often includes frequent moisturizing with gentle, hypoallergenic skin-care products. Psoriasis patients could expect their doctors to suggest products that contain salicylic acid and retinoids, which can help to reduce the symptom of skin thickening.