Why are my eye lids so dark?

Dark Eyelids: Other causes of dark circles include: allergic conditions such as hay fever or eczema. The associated itchiness often leads to eye rubbing, resulting in what is sometimes called an "allergic shiner." dehydration. Fatigue. Fluid retention, often caused by smoking; a salt-rich diet; conditions affecting the heart, thyroid, kidney, and liver; or medications that cause blood-vessel dilation.

Too vague: Both eyes? Since birth or recent.