Dermatitis involving the nail folds may cause inflammation and swelling of the nail matrix / bed, and therefore may result in a number of nail abnormalities. Subtypes include irritant contact dermatitis, allergic contact dermatitis, and dyshidrotic eczema. These subtypes may cause similar nail findings including pitting, Beau's lines, twenty nail dystrophy, transverse or longitudinal ridging, transverse depressions, and onycholysis. The nail fold will invariably show edema and inflammation. In addition to the nail plate abnormalities and nail fold involvement, the fingers and hands should also show evidence of dermatitis. Nail findings are more common in patients who have dermatitis for a longer duration. The severity of dermatitis does not necessarily parallel the severity of nail changes.
Atopic dermatitis affecting the hands and digits may cause nail changes in children. Physical examination findings are similar to those seen in adults.