الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 140 |  |  |
| | | from | 140 | | |
Abstract
Alopecia areata is a medical condition which can affect men, women and children. It often appears as well – defined circular bald patches on the scalp. Many people will get just one or two patches, but for some, the hair loss can be extensive. Unfortunately, children who develop AA before puberty are most likely to develop more extensive and persistent hair loss. Hair loss that spreads to cover the entire scalp is called AT, If it spread to over the entire body, affecting scalp, eyebrows, lashes, beard, pubic hair and every thing else, then the condition is called AU . There are several hypothesis proposed the etiology of AA, such as genetic susceptibility, atopic state, non specific autoimmune reactions, neurological factors, infectious agents and possible emotional stress. Current concepts of AA pathogenesis suggest that AA is a non scarring, inflammatory, cell-mediated disease. A perifollicular and intrafollicular mononuclear cell infiltrate of primarily CD4+ and CD8+ cells are closely associated with dystrophic anagen stage hair follicle, which suggests that T cells and cytokines play an important role . Reactive oxygen species is a collective term including oxygen free radicals such as superoxide and hydrogen peroxide and some non radical derivatives which may yield free radicals in the presence of transitional metal ions . During inflammatory disorders, cells generate reactive oxygen species ROS. When produced in excess, ROS brings about an imbalance in the antioxidant pathway. This imbalance of pro-oxidants and antioxidants in which pro oxidants exceed in concentration is referred to Summeryٍ 101 as “oxidative stress”. Oxidative stress is very harmful to cells including cells in hair follicles . Antioxidant inhibits oxidation of a target molecule by a free radical attack. They are either preventive inhibitors (prevent the initiation of free radical attack) as catalase and SOD or chain breakers as vitamin E and ascorbic acids. These chain breakers convert free radicals to stable products thus block free radical chain reactions. SODs are closely related enzymes that catalyse the breakdown of the superoxide anion into oxygen and hydrogen peroxide. SOD is considered the most effective antioxidant so it is the first line of defense against superoxide free radicals in the body. Catalase its activity is highest in the subcutis. It converts hydrogen peroxide in to water and molecular oxygen. Though it has low affinity for substrate , the reaction capacity is high . Previous data on role of oxidative stress in pathogenesis of AA are very limited and the results are controversial. The aim of this work was to throw light on the etiopathogenesis of AA through detection of lipid peroxidation ,oxidant and antioxidant activity in blood samples and scalp tissue of patients with this disease entity . In this study 35 patients with AA were included. Any subject with any of the following was excluded; Concomitant dermatological or systemic disease, obesity, smoking, excessive exercise apart from daily life activities, use of any treatment including vitamins and anti inflammatory drugs in last 3 month, progressive hair loss and recurrent AA attack(s). 30 age and sex matched healthy controls were choosen as a control group. Every case and control was subjected to blood sampling for measurement of serum levels of SOD, catalase MDA, TAC, TOC Summeryٍٍ 102 and OSI. Scalp biopsy was taken from 10 cases and 10 controls for measurement of tissue SOD and catalase levels. In the present study , the level of SOD was found significantly higher in AA cases than in healthy controls. Also there was a significant positive correlation between serum SOD level and age of patients. Regarding disease severity, the present study demonstrated that higher level of serum SOD was significantly associated with moderate and severe AA. Also significantly higher SOD level was in favor of cases with negative family history of AA . In the current study , serum catalase level was significantly higher in AA cases than in controls . However higher level of the enzyme was significantly present in cases with severe AA . In the present study , the level of MDA was found significantly higher in AA cases than in healthy controls . Regarding disease severity , the present study demonstrated that high level of serum MDA was significantly associated with moderate and severe AA . Also significantly higher MDA level was in favor of cases with negative family history of AA . Regarding site of AA, high level of MDA was significantly associated with AA in sites other than scalp . In the current study , there was a significantly high positive correlation between serum MDA with SOD . Also a significant correlation between serum MDA and catalase level was found. Regarding tissue examination, the current study showed significantly higher enzymatic activity of SOD in tissue of patients with AA compared with healthy control . But there were non significant correlation between tissue and serum SOD .