Why Do I Have Dark Circles Under My Eyes?

6. Allergies

Allergic reactions are another possible cause of dark circles under the eyes. The allergy prompts the release of histamines to combat potentially harmful bacteria. These histamines can cause the eyes to become puffy and dry, both of which contribute to dark circles. Histamines also causes blood vessels to dilate, making them more visible. Some people have the urge to scratch or rub their eyes when they have an allergic reaction, which often exacerbates the shadows. Individuals with hay fever usually have the most obvious “smudges” underneath their eyes.