This book aims to understand the vast field of allergic diseases. Allergies refer to the diseases which are caused by the vulnerability of our immune system when it is exposed to dust particles or other microorganisms present in the environment. Some common allergies are related to food, pollens, dust particles, insect bites, etc. Some allergies can be critical and cause death like asthma or anaphylaxis. This book unravels the recent studies in the field of allergic diseases. The topics covered in this book offer the readers new insights in this field. This book will help new researchers by foregrounding their knowledge in this branch. It will serve as a valuable source of reference for anyone interested in the subject.