Iron deficiency anemia (IDA) is characterized by low red blood cell count and insufficient iron absorption or excess loss, prevalent among children, pregnant women, and the elderly. Diagnosis involves clinical signs and laboratory findings such as microcytic hypochromic red cells, while treatment options include oral and parenteral iron therapies, alongside dietary changes. Common symptoms include fatigue, pallor, and specific changes in nails and skin, with risk factors including nutritional deficiencies and blood loss.