Primary adrenal insufficiency, or Addison's disease, is very rare in the pediatric population. The diagnosis of Addison's disease is usually suspected in the presence of hyponatremia and hyperkalemia, or when adrenal crisis develops. Pediatricians often are unaware of other presenting symptoms of the disease. As a consequence, diagnosis is often delayed by months and even years. One of the presenting signs of adrenal insufficiency is hyperpigmentation. We present the diagnosis of Addison's disease in an 11-year-old boy complaining of skin color changes that were misinterpreted as "progressive cyanosis". When skin color changes occur in a child, pediatricians should think of hyperpigmentation as a presenting sign of adrenal insufficiency.