What Causes Koilonychia?

Higher Altitudes

Koilonychia can be caused by an individual's long-term residence at higher altitudes. The atmospheric air an individual breathes in becomes thinner as they go up in elevation from sea level. While the air technically contains the same 20.9 percent oxygen content at all elevations, the lower pressure at higher elevations decreases the amount of effective oxygen an individual is able to breathe in. For example, the amount of effective oxygen sits at 20.9 percent at sea level, and an elevation of five thousand feet above sea level only yields 17.3 percent effective oxygen. An elevation of ten thousand feet yields a further decreased 14.3 percent oxygen, which falls just below ten percent effective oxygen at an altitude of approximately twenty thousand feet. The body receives less oxygen at high altitudes, making less oxygen available for cells around the body. The body responds by increasing its production of red blood cells, causing a depletion in iron stores and resulting in iron deficiency anemia.

Learn more about what can result in koilonychia now.