behet 's disease ( bd ) is a chronic multisystem disease characterized by oral and genital aphthae ; arthritis ; cutaneous lesions ; and ocular , gastrointestinal , and neurologic manifestations . it was first described by the turkish dermatologist hulusi behet in 1937 as  recurrent oral aphthous ulcers , genital ulcers and  hypopyon - uveitis  . all the criteria for bd recognized by the international bd study group are based on clinical signs and symptoms , except for the pathergy test ( pt ) . this study was performed on 23 patients with bd ( 14 female and nine male ) , their ages ranged between 18 - 60 years . all of the behet patients were in active period of the disease and had two of the disease symptoms at least . the patients did not use colchicine , steroids , or nonsteroidal antiinflammatory drugs ( nsaids ) for at least 10 days before the test . disposable / sharp needles of type 20 g no . 1 were used in the tests . hairless and avascular regions in the flexor parts of both forearms were selected as test regions . the occurrence of erythema without any induration was considered as  negative  and the occurrence of papules and pustules was considered as  positive .  after 48 h from the injection , biopsy was performed on positive pathergy lesions of behet 's patients for histopathological examination . results are expressed as mean  standard deviation ( sd ) or frequency ( % ) . chi - square test was used for comparing histopathological findings and p < 0.05 was considered to be statistically significant . results are expressed as mean  standard deviation ( sd ) or frequency ( % ) . chi - square test was used for comparing histopathological findings and p < 0.05 was considered to be statistically significant . of the specimen from positive pt lesions of patients with bd , nine revealed mixed type inflammatory cell infiltration ( 39.1% ) [ figure 1 ] , two revealed lobular panniculitis without vasculitis [ figure 2 ] ( 8.7% ) , two revealed neutrophil rich infiltration ( 8.7% ) , and five revealed lymphocyte rich infiltration ( 21.7% ) at the subcutaneous tissue . there was no statistically significant difference between subcutaneous tissue findings and sex , family history , and systemic involvement . in dermis , ten ( 43.4% ) revealed mixed type inflammatory cell infiltration , three ( 13.0% ) revealed perivascular cell infiltration , two ( 8.6% ) revealed lymphocytic vascular reaction , four ( 17.3% ) revealed endothelial swelling and thickening , and six ( 26.0% ) revealed erythrocyte extravasation . six ( 26.0% ) showed pustule formation [ figure 3 ] in epidermis and five were subcorneal , and one was intraepidermal . also , eight revealed vasculitis ( 34.7% ) out of which three ( 13.0% ) were lymphocytic vasculitis and five ( 21.7% ) were leukocytoclastic vasculitis [ figure 4 and table 2 ] . there was no statistically significant difference between dermal histopathologic findings and sex , family history , and systemic involvement except ocular involvement . uveitis was found to be statistically significant in the patients who revealed vasculitis ( p = 0.012 ) . mixed inflammatory cell infiltration in the dermis ( h and e , 20  10 ) lobular panniculitis without vasculitis ( h and e , 20  10 ) subcutaneous histopathologic findings of positive pathergy test epidermal pustule formation ( h and e , 4  10 ) leukocytoclastic vasculitis ( h and e , 20  10 ) dermal histopathologic findings of positive pathergy test pathergy is the term used to describe hyperreactivity of skin that occurs in response to minimal trauma . the pt first reported by blobner is the skin hyperreactivity associated with erythema , papules , or pustules which is induced by intradermal prick in some patients with bd . the clinical use of pt is very important in the diagnosis of bd . on the other hand , misinterpretation of test for that reason , immunopathologic and histopathologic tests are recommended with pt . however , there is also controversy about the histopathology of pathergy reaction . some authors claim mixed infiltration , while authors report neutrophilic infiltration with leukocytoclastic vasculitis . a possible explanation for this discrepancy may be the different methods used to induce lesions ( needle prick , histamine injection , etc . ) , variations in biopsy time , and ethnic origin of patient . the histopathologic result of pt depends on the time of biopsy . in the first 6 h , polymorphonuclear leukocytes are dominant in inflammatory exudate . after 24 h , mononuclear cell infiltration in dermal vessels , edema in vessel endothelium , and edema and leukocytoclasia in reticular dermis leukocytoclastic vasculitis and neutrophilic vascular reactions also occur after 24 h. lymphocytic vasculitis and lymphocytic perivascular infiltrations are found later . in histopathology of the pt , the perivascular and periadnexal lymphohistiocytic infiltration of varying intensity and their penetration in deep dermis and moderate neutrophilic infiltration in dermis are also important findings . in our study , mixed type inflammatory cell infiltration , lobular panniculitis without vasculitis , neutrophil rich infiltration , and lymphocyte rich infiltration were found to be the subcutaneous histopathologic findings of positive pt in bd . in the literature ; panniculitis , lobular or mixed septal , and lobular in pattern was shown in erythema nodosum - like lesions of bd . vasculitis was noted in most erythema nodosum - like lesions in bd . in our study , lobular panniculitis observed in two patients ; but interestingly , there was evidence of vasculitis . up to now , although many studies have investigated clinical and histopathologic findings of pt , panniculitis among the histopathologic findings in pt has never been reported . in our study ; mixed type inflammatory cell infiltration , endothelial swelling and thickening , erythrocyte extravasation , perivascular cell infiltration , and lymphocytic vascular reaction were detected in dermis by histopathologic examinations . uveitis was found to be statistically significant in patients in whom vasculitis was observed . on the light of this finding , the patients that vasculitis was revealed should be more alert against the development of uveitis . this is an exceptional study since it is the first study that determines the subcutaneous tissue findings of positive pathergy reaction in behet patients . however , uveitis was found to be statistically significant in patients who had vasculitis in dermis . it can be a clue for prediction of disease severity and course . further studies that include wide number of patients will better illuminate the correlation between histopathologic findings and disease severity and clinical course . mixed type inflammatory cell infiltration , lobular panniculitis without vasculitis , neutrophil rich infiltration , and lymphocyte rich infiltration were found to be histopathologic findings of positive pathergy test in behet 's disease.panniculitis among histopathologic findings in the pathergy test has never been reported . mixed type inflammatory cell infiltration , lobular panniculitis without vasculitis , neutrophil rich infiltration , and lymphocyte rich infiltration were found to be histopathologic findings of positive pathergy test in behet 's disease .
background : the pathergy test ( pt ) is important in the diagnosis of behet 's disease ( bd ) . 
 however , misinterpretation of the test might cause false - positive or false - negative results . 
 therefore , immunopathologic and histopathologic tests are recommended with pt.aims and objectives : the aim of this study is to determine histopathologic findings of positive pathergy reaction at bd.materials and methods : this study was performed on 23 patients with bd . 
 all patients were in active period of the disease . 
 after 48 h from the injection , biopsy was performed on positive pathergy lesions.results:of the specimen from positive pt lesions of patients with bd , nine revealed mixed type inflammatory cell infiltration ( 39.1% ) , two revealed lobular panniculitis without vasculitis ( 8.7% ) , two revealed neutrophil rich infiltration ( 8.7% ) , and five revealed lymphocyte rich infiltration ( 21.7% ) at the subcutaneous tissue . 
 mixed type inflammatory cell infiltration ( 43.4% ) , endothelial swelling and thickening ( 17.3% ) , erythrocyte extravasation ( 26.0% ) , perivascular cell infiltration ( 13.0% ) , lymphocytic vascular reaction ( 8.6% ) , lymphocytic vasculitis ( 13.0% ) , and leukocytoclastic vasculitis ( 21.7% ) were detected in dermis by histopathologic examinations . 
 there was no statistically significant difference between histopathologic findings and sex , family history , and systemic involvement except uveitis.conclusion:this is an exceptional study since it is the first study that determines subcutaneous tissue findings of positive pathergy reaction in behet patients . in our study , uveitis was found to be statistically significant in the patients who had vasculitis in dermis . 
 it can be a clue for prediction of disease severity and course . 
 further , studies that include wide number of patients will better illuminate the correlation between subcutaneous tissue findings and disease severity and clinical course .