1. Itchy skin with red, raised patches More than your sanity could be at risk with an unknown itch. Flat red patches, raised plaques with a scaly surface, or lumps accompanied by severe itching in some cases can signal lymphoma of the skin, says Debra Jaliman, MD, dermatologist and author of Skin Rules. If the cluster of symptoms sounds familiar, start dialing—only a dermatologist can evaluate if this serious illness is the culprit.  MORE: 9 Things Your Vagina Is Trying To Tell You
  2. A breakout that acne treatments can’t fix  You’ve used every lotion and potion around and, alas, that breakout still won’t budge. That could be because you’re actually suffering from rosacea, a skin condition that causes redness and pus-filled bumps that are nearly impossible to tell apart from a regular breakout, until you’re diagnosed by a pro, says Rebecca Kazin, MD, medical director of the Johns Hopkins Dermatology and Cosmetic Center. Although there’s no cure for rosacea, symptoms can be treated and controlled with Rx creams like ivermectin—an antiparasitic drug—and an oral antibiotic like doxycycline, she says. 
  3. Dry patches that won’t go away If your dry patches stick around, regardless of the umpteen nights you’ve been slathering lotion on them, the skin conditions eczemaor psoriasismight be the real problem, says Kazin. (Both eczema and psoriasis produce red, irritated patches on the skin; however, psoriasis is characterized by white scales on the irritated portion, whereas eczema generally is not.) They’re not life-threatening, but there’s no reason to live with them. Both conditions can be treated and controlled with proper medication: topical or oral steroids or antihistamines, in the case of eczema, and vitamin D creams, topical steroids, oral medications, or ultraviolet light and excimer laser treatments for psoriasis, says Kazin. 
  4. Discolored nails that aren’t stained by polishMedia Platforms Design Team If you’ve ever painted your nails, you know a faint stain post–polish removal is par for the course. But if discoloration is the norm for you, take note. White or yellow nail beds may be a sign of fungal growth, whereas greenish hues can indicate a bacterial infection in or around the nail, Kazin warns. Nail discoloration can also flag liver or kidney disease: Patients with renal failure often have “half-and-half” nails, where nails are white at the base and brown at the tip, she says. Bring up the issue at your next visit to your dermatologist, or sooner if it worsens. (Check out these 9 other things your nails say about your health.)
  5. Pigmented patches on your body If you have light brown patches on your chest and back that look dry and flaky, you may have tinea versicolor, a sweat-induced yeast infection of the skin. (It’s easy to distinguish from the common pigmentation disorder melasma, which usually affects facial skin instead.) Sure, it’s gross, but it’s not a painful or contagious condition. Once you see your dermatologist, the issue can be treated with antifungal creams, lotions, or pills that control yeast, says Kazin. 
  6. Scaly patches lotion can’t help  Scaly patches on the skin can be a sign of ringworm, says Jaliman. Despite its name, there’s no actual worm involved (whew!). It’s a fungal infection that develops on the top layer of skin; you’ll know it by the red, circular rash with clearer skin in the middle. Typically, those with ringworm have dogs or cats with the same problem, explains Jaliman. Thankfully, it can be easily identified and treated with a prescription cream or antifungal pill. “Your doctor will take a scraping and look at it under the microscope to be sure,” says Jaliman.  MORE: 9 Ways Therapists Can Tell If Your Relationship Is Going To Survive
  7. Hair that’s suddenly thinner  9 causes of hair loss in women, and how to treat them We probably don’t have to tell you to head to the doctor if you’re losing hair, but there are a number of factors that can bring it on: One common type of hair loss, typically caused by stress, is alopecia areata, which looks like a circular bald patch and can be treated with cortisone injections. Another stress-related cause of hair loss is telogen effluvium, which can result in loss of up to 20% of hair and usually shows up about 2 to 3 months after pregnancy, surgery, illness, or some type of extreme shock to the body, Kazin says. (Check out these .) Hair typically comes back on its own after telogen effluvium, though your dermatologist may suggest oral finasteride or topical Rogaine to power up regrowth. Finally, sudden hair loss could be a sign of either hypo- or hyperthyroidism, which can be determined by a blood test and treated with oral medications, says Jaliman.