Not every case of type 2 diabetes presents with the obvious symptoms—unquenchable thirst, nonstop bathroom trips, and numbness in your hands or feet. Look out for these other subtle signs that something may be amiss with your blood sugar.

1. YOU'VE NOTICED UNPLEASANT SKIN CHANGES

Dark, velvety patches in the folds of skin, usually on the back of the neck, elbows, or knuckles, are often an early warning sign of too-high blood sugar levels. Although genetics or hormonal conditions can cause the skin disorder, called acanthosis nigricans, "when I notice the patches, the first thing I do is test my patient's blood sugar," says Sanjiv Saini, MD, a dermatologist in Edgewater, Maryland.

"High insulin levels promote the growth of skin cells, and melanin, a pigment in these cells, makes the patches dark." The test may show that the patient already has diabetes, but, more likely, it will detect higher-than-normal blood sugar levels, suggesting the patient is on the way to developing the disease, explains Saini. Losing weight—as little as 10 pounds—will likely lower blood sugar levels and help the condition clear up. Otherwise, he says a dermatologist can treat it with laser therapy or topical retina A.

2. YOUR VISION IMPROVED OUT OF NOWHERE

Sorry, suddenly being able to ditch your glasses probably isn't good news: "You'll often read that blurry vision is as a diabetes symptom when, in fact, vision can change for better or worse," says Howard Baum, MD, an assistant professor of medicine in the diabetes division at Vanderbilt University. "I've had patients tell me that their vision has improved when their blood sugars were elevated, and then after they start treating their diabetes, they needed their glasses again." What gives? Diabetes causes fluid levels in the body to shift around, including inside your eyes, which leads to the erratic eyesight.

3. YOU HAVE UNRELENTING ITCHINESS

Think it's silly to mention scratchy skin to your doctor? Not so. Diabetes impairs blood circulation, which can lead to dryness and itchiness. "Some of my newly diagnosed diabetes patients mention they're itchy on their extremities—the hands, lower legs, and feet—so it's something doctors should consider in conjunction with other symptoms," says Baum. If regular use of a moisturizer doesn't fix the itch, bring it up at your next appointment.