A Dennie–Morgan fold, also known as a Dennie–Morgan line or an infraorbital fold and sometimes as the Allergic Salute and the Dennie's Sign, is a fold or line in the skin below the lower eyelid caused by edema in atopic dermatitis. The presence of Dennie–Morgan folds is used as a diagnostic marker for allergy with a sensitivity of 78% and specificity of 76%.
The pathophysiology of this sign is not clear. One proposed mechanism is that continuous spasm of the Muller eyelid muscle and skin edema could be due to hypoxia from poor circulation.
Dennie–Morgan fold should not be confused with allergic shiners or dark circles which are 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. Allergic shiner is less sensitive than Dennie–Morgan fold.