Dennie–Morgan fold
A Dennie–Morgan fold, also known as a Dennie–Morgan line or an infraorbital fold, is a fold or line in the skin below the lower eyelid. It can simply be an ethnic/genetic trait, but was found in one study to occur in 25% of patients with atopic dermatitis. The presence of Dennie–Morgan folds can be used as a diagnostic marker for allergy with a sensitivity of 78% and specificity of 76% according to one study.
Such folds are also common among certain ethnic groups such as Africans, Tatars, Slavs, Balts, and Finno-Ugric peoples and are not known to be associated with any medical condition in these.
The pathophysiology of this sign is not clear. One proposed mechanism is that continuous spasm of the superior tarsal muscle and skin edema could be due to hypoxia from poor circulation.
A Dennie–Morgan fold should not be confused with an "allergic shiner", a purple-gray discolouration beneath the lower eyelid. This is related to the accumulation of blood and other fluid in the infraorbital groove resulting from nasal congestion.
