7 Skin Rashes You Should Always Take Seriously

Your skin may be the first sign of chronic medical conditions you shoudn’t ignore.

When it comes to protecting your birthday suit, you may be highly accustomed to looking for changes in moles, which may be a symptom of skin cancer—but that’s not all you need to keep our eyes peeled for. Sometimes what seems like a simple rash, discoloration, or patch of dry skin isn’t just a minor thing that won’t go away on its own. Some can signal skin problems that raise your risk for serious medical problems, while others may be tip-offs to health issues that are more than skin deep. Here’s the scoop on seven conditions that shouldn’t be ignored.

1. Raised, red, scaly, or crusty patches: Could be psoriasis

If they’re covered with a silvery white buildup of dead skin cells, you probably have plaque psoriasis, the most common form of psoriasis. (These are other signs your skin problems are likely psoriasis.) While scientists don’t know the exact cause of psoriasis, “we know there’s a genetic proclivity to it,” says Mona Gohara, MD, associate clinical professor of dermatology at Yale School of Medicine. “Patients will always have that, then something triggers psoriasis to flare—strep throat or a medication are two common triggers.”

The upshot: With psoriasis, skin cells grow at an abnormally fast rate, which causes them to stack up and become thickened patches. The patches, which often show up on the scalp, knees, elbows, and lower back, are often itchy and painful, and they can crack and bleed. If that’s not bad enough, the chronic inflammation associated with psoriasis can also damage arteries and lead to an increased risk of heart attack and stroke.

Research shows that some treatments reduce cardiovascular risk, so it’s important to take action if you suspect you might have psoriasis, which can develop at any age, but usually first strikes between 15 and 30. If you develop a rash that doesn’t go away with an over-the-counter medication, the National Psoriasis Foundation suggests contacting your doctor.

2. Frequent facial flushing: Could be rosacea

If you often get red in the face, you may have rosacea, a condition that mostly affects fair-skinned people of northern European descent. Experts aren’t sure what causes rosacea, which, in addition to a flushed look, is often accompanied by tiny, acne-like bumps—hence the reason the condition is often wrongly referred to as “adult acne.”

While the exact cause of rosacea is unknown, what is clear is that the condition is progressive and—if left untreated—can worsen over time, says David Bank, MD, a dermatologist in Mount Kisco, NY, and author of the book Beautiful Skin. “The redness often becomes ruddier and more persistent, and visible blood vessels may appear.” In its extreme form, rosacea causes the nose to grow swollen and bumpy from excess tissue, a condition known as rhinophyma. Rosacea is also associated with a host of serious medical issues, including high blood pressure and high cholesterol, so it’s important to seek a medical evaluation of your skin and, if appropriate, have a general health exam as well.

There’s no cure for rosacea, but treatment—including topical and oral antibiotics—usually helps control the problem. Figuring out, and avoiding, your individual rosacea triggers can go a long way toward minimizing flare-ups. The most common tripwires, according to a survey by the National Rosacea Society, are sun, emotional stress, hot weather, wind, heavy exercise, and alcohol. Indeed, recent research found that women who drank alcohol had an elevated risk of developing rosacea, and the more they imbibed, the higher the risk.

3. Red, itchy, easily irritated skin: Could be eczema

Eczema is a catch-all term for a number of chronic disorders that leave the skin red, easily irritated, and itchy (hence its nickname, “the itch that rashes”). The condition manifests itself in so many ways that the father of modern dermatology defined it this way: “Eczema is anything that looks like eczema.”

While the exact cause of eczema is unknown, the National Eczema Association reports that people develop eczema because of a combination of genes and environmental triggers: When an irritant or an allergen from inside or outside the body “switches on” the immune system, it produces inflammation—and it’s this inflammation that causes the symptoms common to most types of eczema.

There are many types of eczema: Atopic dermatitis usually occurs in infancy and early childhood and becomes less severe with age. The most common type of eczema in adults is contact dermatitis, which occurs when skin comes in contact with irritating (think detergents or solvents) or allergenic (like poison ivy) substances. (Here are tips for showering with eczema and tips for doing laundry with eczema.) Eczema can’t be cured, but it can be controlled, so talk to your doctor if you think you have it. Research shows adults with eczema may also have an increased risk of heart disease and diabetes, and working with your doctor can help reduce the stress associated with the condition as well as improve lifestyle factors that can both ease your symptoms of eczema and lower your risk for other health problems.

4. Dark patches of thickened skin with a velvet-like appearance: Could be diabetes

There are at least a dozen skin conditions associated with diabetes, but only a couple that commonly serve as tip-offs of the disease. One, acanthosis nigricans, is a dark patch of thickened skin that feels like velvet. It usually develops on the back of your neck or armpit and is often the first sign of prediabetes, a condition in which your blood sugar levels are higher than normal but not high enough to be called diabetes. The second, granuloma annulare, are red or skin-colored raised bumps that usually crop up on the backs of the hands, arms, and feet. Whether the condition actually signals diabetes is debatable: While most people who have granuloma annulare don’t have diabetes, a number of studies have found it in people who do have the disease. For now, doctors recommend getting tested for diabetes if you these kinds of bumps, especially if they come and go.

5. Red bumps on your shins, ankles, and sometimes arms: Could be bowel disease

After arthritis, skin disorders represent the next most common non-intestinal complication of inflammatory bowel disease (IBD), reports the Crohn’s & Colitis Foundation. Luckily though, they only affect about 5% of people with IBD. The most common is erythema nodosum, which literally means “red bumps.” These tender red nodules, a disorder of the fat that lies below the skin, appear over the shins and ankles and sometimes the arms. The disorder, which usually affects women more than men, generally appears in conjunction with a flare-up of IBD, but it also may occur just prior to one. Either way, it tends to resolve when the bowel disease is brought under control.

6. Dry, scaly, cold, itchy skin: Could be a thyroid problem

The thyroid may be just a small gland located at the base of your neck, but if it’s not producing enough of the hormones that control the way the body uses energy (a condition known hypothyroidism, or underactive thyroid), the skin can pay the price—becoming dry, scaly, cold, pale, and itchy. Since hair and nails are made of the same protein as skin, they can be affected too, leaving hair dry and nails brittle. Your doctor can confirm a thyroid disorder by ordering a series of blood tests, and prescription meds to replace the hormones your own thyroid no longer makes can help get your hormonal levels back to where they should be.

7. A butterfly-shaped rash on the cheeks and nose: Could be lupus

It’s not surprising that the autoimmune disease lupus was first described as a dermatologic condition: One of the four types of lupus, cutaneous lupus erythematosus, only affects the skin, and systemic lupus erythematosus, the most common form of the disease, often shows up in the skin—researchers say up to 80% of people with it will see some type of effect on their skin during the course of the disease.

The key skin clue for lupus is a butterfly-shaped rash that stretches across the cheeks and over the nose. “It’s classic,” says Dr. Gohara. People with lupus are also typically very sensitive to ultraviolet light, and just a short amount of time in the sun can cause lupus to flare or worsen, leading to rashes or sores on sun-exposed areas of the body, or in the mouth, nose, or vagina. Cutaneous lupus can also cause a type of reaction called discoid rash, so-called because the raised, scaly, red (but not itchy) rash looks like disks or circles.

Lupus strikes mostly women of childbearing age, but men, children, and teens can develop it too, reports the Lupus Foundation of America. If you have any of these symptoms, talk to your doctor about getting an antinuclear antibody (ANA) test, which is the test for autoimmune diseases. There’s no cure for lupus, but it can be managed with a combination of lifestyle changes and medications.