Sean Klepper M.D.
Artur Zembowicz M.D....
- Cell-mediated (type IV) immune response to topical agents.
- Commonly implicated inciting substances include nickel, poison ivy, synthetic rubber and topical medications.
- Presents as pruritic erythematous papules and plaques with vesicles at the site of contact with the offending agent.
- Often not distinuishible histologically from other causes of the spongiotic reaction pattern, and clinical history is required to arrive at an exact diagnosis
- Spongiosis, often with intraepidermal vesicle formation
- Papillary dermal edema
- Irregular psoriasiform hyperplasia (in subacute and chronic spongiotic dermatitis)
- Upper dermal perivascular lymphocytic infiltrate
- Exocytosis of eosinophils is sometimes present.
- Scale crust formation
- Among these features, larger intraepidermal vesicles and more dermal edema may be seen in allergic contact dermatitis than in spongiosis of other etiologies, and these may be helpful in pinpointing the diagnosis.