Effect of Narrow Band UVB on normal flora of lesional and normal skin in psoriatic patients

Psoriasis is a chronic inflammatory dermatosis that affects 0.6% to 4.8% of the general population. Our aim was to compare the effect of narrow band UVB (NB-UVB) on normal flora of cutaneous plaques and normal skin in psoriatic patients. Twenty psoriatic patients without any contraindication of phototherapy were enrolled in this study. Samples from psoriatic lesions and adjacent normal skin, before and after phototherapy with NB-UVB were taken. Patients were treated with NB-UVB three times weekly until complete remission. Finally, quantity of normal cutaneous flora on normal and involved skin, before and after treatment was compared. The mean±SD of the NB-UVB sessions and the mean cumulative dose were 26.35±4.95 and 2.05±0.57 J/cm2, respectively. The number of Staphylococcus epidermidis, S. aureus and diphtheroids on psoriatic plaques reduced after phototherapy.Conclusuion: The quantity of normal cutaneous flora on normal skin is less than psoriatic plaques, and it reduced on normal and involved skin after phototherapy.