Atopic eczema typically presents in flexural areas with ill-defined borders, whereas ACD has sharp, geometric borders that correspond to the site of allergen contact.
While often allergic, this diagnosis is specific to the eyelid location, whereas "Allergic contact dermatitis" is the general term for the underlying mechanism.
This is a location-specific diagnosis; it can be distinguished from generalized ACD if the trigger is confined to the feet (e.g., shoe components).
Like foot dermatitis, this is defined by its location and is often a mix of irritant and allergic causes, whereas the term "ACD" implies a specific identified allergen.
Psoriasis is distinguished by its sharply demarcated, silvery-scaled plaques on extensor surfaces, a different morphology and distribution than the vesicular, weeping rash of acute ACD.
This is characterized by greasy, yellowish scale in oily areas like the scalp and face, a different quality of inflammation than ACD.
The annular shape with a raised, scaly border and central clearing, confirmed by a KOH test, is the classic sign distinguishing this fungal infection from ACD.
