Dark spots

The presence of dark patches on your skin unexpectedly may suggest adrenal insufficiency (Addison’s disease). However, this is not always the case. Muscle/joint pain, loss of appetite, low blood pressure, and sugar levels are other symptoms. If you observe any of these symptoms, contact your doctor right away.
Discoloration

Have you ever had white patches on your skin? It could be vitiligo, a disorder in which melanocytes no longer produce pigment. If you have this problem, see an endocrinologist or dermatologist for a diagnosis and therapy.