Are respiratory allergic diseases related to atopic dermatitis?

The difference of test results between patients with "pure" atopic dermatit is (AD) and "mixed" AD (with concomitant respiratory allergy, RA) was inves tigated in 30 AD patients. The results showed the onset of disease that mos tly occur in, the early infancy [15 (50%) patients had developed the diseas e under the age of 2-2/10 in pure AD, and 13/20 in "mixed" AD]. Twenty (66. 6%) of them had a history of RA "mixed", AD) whereas the remaining 10 (33.3 %) had "pure" AD. Seventeen (56.6%) AD patients had one concomitant allergi c disease, while 3 (10%) patients had two comorhid conditions (AR and AB) e ach. Family history was positive for atopy in 22 (73.3%) AD patients [in 14 (46.6%) patients in a first-degree relative]. Twenty-four (80%) patients h ad positive prick test [9/10 (90%) in "pure" AD and 15/20 (75%) in "mixed" AD], mostly for house dust (20). Positive scratch test was observed in 16 ( 53.3%) patients [4/10 in "pure" AD, and 12/20 in "mixed" AD]. Nineteen (63. 3%) AD patients showed positive patch test reaction [5/10 in "pure" AD, and 14/20 in "mixed" AD]. AD patients had higher serum IgE (21/30) than non-at opic ones but similar in "pure" AD, and "mixed" AD [7/10 (70%) in "pure" AD , and 14/20 (70%) in "mixed" AD]. Determination of CD23 marker on B-lymphoc ytes showed normal values in 24, and increased values in six patients [2/10 in "pure" AD, and 4/20 in mixed AD]. The values of CD21 were decreased in 16 AD patients [6/10 in pure AD, and 10/20 in "mixed" AD]. HLA-DR expressio n was normal in almost all patients. There were no statistically significan t differences (p<0.05) between the "pure" AD and "mixed" AD patient groups, except for the age at onset, which teas younger in the group of patients w ith concomitant RA. Accordingly, study results pointed to the association b etween AD and RA.