ABSTRACT
Human skin is the anatomical barrier that acts as an imperative screen between internal and external environment and renders defense against pathogens and damage. However, many environmental factors and lifestyle habits in this modernized world contribute to several allergic diseases, which are estimated to be evident in one-third of the general population. These allergic diseases are initiated by an imbalance in the activation of mast cells, which leads to the inammatory mediators (Le et al. 2009). Overproduction of inammatory mediators increases the risk of numerous pathological conditions that include chronic inammatory skin diseases. One skin inammatory disease that needs an effective medicinal approach to be managed is atopic dermatitis (AD). AD is a chronic inammatory skin disease associated with a personal or family history of allergy. AD is a common, often chronic (long-lasting) skin disease that affects a large percentage of the world’s population and involves susceptibility genes, the environment, defective skin barrier function, and immunologic responses (Hamid, Boguniewicz, and Leung 1994). AD can occur at any age, and this pruritic inammation’s lifetime prevalence is 10-20% in children and 1-3% in adults (Leung et al. 2004). The fundamental lesion in AD is a defective skin barrier that results in dry itchy skin and is aggravated by mechanical injury inicted by scratching. This allows entry of antigens via the skin and creates a milieu that shapes the immune response to these antigens (Oyoshi et al. 2009). AD is categorized into two types based on molecular responses. One is termed “extrinsic” and involves immunoglobulin E (IgE)-dependent sensitization that makes up to 70-80% of the patients, and the other form is known as “intrinsic” and involves IgE-mediated sensitization that makes up to 20-30% of the patients worldwide (Novak and Bieber 2003). Both forms of AD have associated eosinophilia. In extrinsic AD, memory T cells expressing the skin-homing receptor,
25.1 Introduction ..........................................................................................................................303 25.1.1 Pruritic Skin Inammation .......................................................................................303 25.1.2 Pharmacognosy and Importance of Marine Algae ..................................................304
