Darkened skin on particular parts of the body, such as the neck, elbows, armpits, knuckles and knees, is a condition known as acanthosis nigricans and is a possible sign of prediabetes. However, prediabetes often presents no outward symptoms, as stated by Mayo Clinic.
Frequently, patients do not have any warning signs of diabetes until they have already entered type 2. Signs of this condition include blurry vision, fatigue, a frequent need to urinate and an increase in thirst. Because prediabetes so often presents with no symptoms, doctors instead recommend that patients look for a series of risk factors that should be self-monitored. Patients concerned about their condition should visit their physician, according to Mayo Clinic.
Some of the risk factors for type 2 diabetes include a sedentary lifestyle, an age of 45 or above, a family history of type 2 diabetes, having a body-mass index higher than 25, a history of gestational diabetes, having given birth to a baby heavier than 9 pounds, high blood pressure, an HDL cholesterol below 35 milligrams per deciliter, triglyceride levels above 250 milligrams per deciliter, or polycystic ovary syndrome. People who are African American, Asian American, American Indian, Hispanic or a Pacific Islander also have an elevated risk of type 2 diabetes, notes Mayo Clinic.