INTRODUCTION: Former investigations of Koebner phenomenon had demonstrated its 
higher incidence in patients with severe generalized and/or unstable forms of 
psoriasis which expressed increased resistance to various treatment modalities. 
The aim of this study was to establish the correlation between the presence of 
Koebner phenomenon and the PUVA therapy effects, total number of PUVA 
treatments, total dose of UVA radiation and the duration of remission after PUVA 
therapy discontinuation.
MATERIAL AND METHODS: Sixty patients with severe clinical picture of psoriasis 
vulgaris, treated with PUVA therapy, were included in this research. According 
to the presence of Koebner phenomenon they were divided into two groups, 20 
patients with positive and 40 patients with negative Koebner reaction, who were 
the control group at the same time.
RESULTS AND DISCUSSION: 95% of patients treated with PUVA, were cleared of 
psoriatic changes in the Koebner positive, as well as in the Koebner negative 
group. There were also no differences between the Koebner positive and Koebner 
negative group in the mean number of PUVA treatments, mean total dose and the 
last dose of UVA radiation, which led up to the clinical remission of psoriasis. 
Our results of investigation have demonstrated increased relapse of psoriasis, 
during the first 6 months after cessation of PUVA therapy, in the Koebner 
positive group, with a high statistical significance (p < 0.001), comparing with 
Koebner negative group in the same period. Furthermore, the tendency of relapse 
of Koebner positive and Koebner negative psoriatic patients was higher in 
Koebner positive group even in the first 3 months after PUVA therapy.
CONCLUSIONS: PUVA therapy effects, total number of PUVA treatments, total dose 
of UVA radiation didn't depend on presence of Koebner phenomenon. However, 
Koebner phenomenon was a mark of high relapsing tendency of psoriasis in the 
first 6 months after PUVA therapy cessation.