Allergic diseases or allergy is the uneasiness caused due to the presence of some allergens like pollens, food items, grasses, dogs, cat fur etc. Generally allergic people are more sensitive to these substances which may cause swelling, sneezing, red eye and itching. Sometimes a long exposure to these materials may be life threatening. Accurate diagnosis and identification of the allergen responsible is quite crucial for clinicians to provide the curative measures. This book brings forth some of the most innovative concepts and elucidates the unexplored aspects of allergic diseases. It strives to provide a fair idea about potential allergy causing substances and treatments already available and new entrants to the list. It aims to serve as a resource guide for students and experts alike and contribute to the growth of the discipline.