A longitudinal study of contact sensitivity in patients with atopic dermatitis.

Sensitization trials with dinitrochlorobenzene (DNCB) were performed in 150 patients with atopic dermatitis (AD) (24 severe, 86 moderate, and 40 mild cases). Dinitrochlorobenzene challenge tests were positive in 33% (8/24) of severe cases, in 95% (82/86) of moderate cases, and in 100% (40/40) of mild cases, indicating that DNCB contact sensitivity is diminished only in patients with AD who have extensive skin lesions. Of the 20 patients who were nonreactive on the first DNCB challenge tests, 18 became reactive on the second challenge tests that were performed at the time when the dermatitis was well controlled. It is likely that the suppressed contact sensitivity seen in patients with AD is secondary to the disease.