Clinical and Laboratory Study of a Photodynamic therapy and Flash Lamp Pulsed Dye Laser for Chronic Plaque Psoriasis

Abstract

Psoriasis is a chronic disease characterized by inflammation and keratinoncytes proliferation. It affects 1-3% of population and the incidence is equal in males and females. In the year 2008, 685 patients were found to be affected with psoriasis out of 64684 who attended Khartoum Dermatology Teaching Hospital. The incidence was 1.06%. Psoriasis has presents a therapeutic challenge to physicians specially the chronic plaque psoriasis resistant to conventional methods of treatment. This study showed that the use of standard flashlamp pulsed dye laser (FLPDL) with epidermal cooling in the treatment of chronic plaque psoriasis was effective and could be used as an alternative therapy in patients not responding to other types of treatment. Photodynamic therapy can be used as an alternative laser therapy for chronic plaque psoriasis if pulsed dye laser is not available. Till now there are no documented studies about using FLPDL and photodynamic therapy in treating chronic plaque psoriasis in Sudan, So in this study we used FLPDL and photodynamic therapy as alternative modalities to clear psoriatic plaques, to improve the cosmetic appearance of patients and decrease their psychological trauma. The standard FLPDL is considered now an important way of treating resistant chronic plaque psoriasis. The wavelength of this laser is 595nm, and the pulse duration is 0.45mes. The mode of action depends on the theory of selective photothermolysis to cause thermal coagulation of the dilated papillary dermal vasculature, preventing the access of activated T lymphocytes to reach the skin. IX The standard FLPDL systems are usually associated with epidermal cooling techniques to prevent non- selective thermal damage of the epidermis. Study design: This is a fractional experimental study, testing the effects of FLPDL and the photodynamic therapy with different parameters on chronic plaque psoriasis. Study area: This study was conducted in Laser Institute, Sudan University, plastic surgery department in Khartoum Teaching Hospital, and Khartoum Dermatology Teaching hospital, during the period from June 2009 to August 2010 Objective: The general objective of this study is to test the effect of FLPDL and photodynamic therapy on chronic plaque psoriasis in Sudanese patients and compare the result with topical conventional PUVA therapy, while the specific objective is to evaluate the clinical and histological response of treating chronic plaque psoriasis in Sudanese patients Subject, Materials and method: The laser medical system used in this study was the FLPDL with a dynamic cooling device while the laser medical system used for photodynamic system were continuous diode lasers with different wavelengths and output power to activate the chemical photosensitiser (Topical 20%- Aminolevulinic acid hydrochloride solution). For topical PUVA therapy we used methxsalen 0.2% solution as a photosensitiser which was activated by long wavelength ultraviolet radiation (UVA) 35 patients with chronic plaque psoriasis were included in this study. 24 patients were treated with photodynamic therapy, 3 patients treated with FLPDL, and 8 patients treated with topical PUVA therapy. Some patients were treated in the Institute of laser, Sudan University; others X were treated in plastic surgery department in Khartoum Teaching Hospital, during the period between June 2009 to August 2010 Before starting laser therapy, the usual laser safety precautions were checked, especially the eye goggles for the medical staff and the eye shields for the patients. For FLPDL the desired fluence was adjusted as follows: 10J/cm2 for plaque A 10.5 J/cm2 for plaque B 11 J/cm2 for plaque C The dynamic cooling device was 30ms with 10ms delay For photodynamic therapy, 4 patients received 542nm diode laser radiation, 4 mW output power for 15 minutes. Another 4 patients received 657nm diode laser radiation, 16 mW for 15 minutes. Out of the last 12 patient’s, 4 patients received 671 diode laser radiation , 50mW output power for 15 minutes, 4 patients received 671nm diode laser, 100mW power for 10 minutes, 8 patients received 671 diode laser radiation, 100mW output power diode laser radiation for 15 minutes. Results and Discussion: This study showed that chronic plaque psoriasis responded to the treatment by the pulsed dye laser, 67% of patients with chronic plaque psoriasis achieved complete clearance of their lesions, 33% achieved 50% reduction in PSI. None of the patients showed no or poor response after flashlamp pulsed dye laser (595nmFLPDL) therapy. For photodynamic therapy, 17% achieved complete clearance, 12% achieved 75% reduction in PSI, and 46% achieved 50% reduction in PSI. 17% achieved 25% reduction in PSI, and 8% showed no response. Treatment of chronic plaque psoriasis by the conventional method was either ineffective or achieved poor results in chronic plaque psoriasis XI Conclusion and Recommendation: The use of FLPDL with epidermal cooling is an effective method of treating chronic plaque psoriasis, and should be considered in patients not responding to other types of therapy Photodynamic therapy gave variable results and needs further research work Topical PUVA therapy should not be considered in the treatment of chronic plaque psoriasis, because it gave poor results. This study offers a basic study for further studies dealing with treating chronic plaque psoriasis with FLPDL and photodynamic therapy. The Laser clinic in Khartoum Dermatology Teaching Hospital should be supplied with more appropriate modern equipments and trained doctors and technologist Coordination between the laser clinic and other clinics especially the plastic surgery clinics in the country Further studies using laser in the treatment of chronic plaque psoriasis are mandatory.