Question

What is Auto-immunity?

Answer 1

Hint: Usually, the immune system acts as a defense against infections and certain diseases. It is constituted by various organs, cells, and proteins (antibodies). It functions to identify, attack, and destroy germs and other foreign particles. At times, the immune system performs a mistake and attacks its own tissues, and organs. This phenomenon is called autoimmunity.

Complete answer:

                                                   Fig.: Causes of Autoimmunity
When the body senses danger from an infection or virus, the immune system attacks, which is an immune response. But occasionally, healthy tissues and cells are caught up during this response, resulting in the formation of autoimmune disease.
A significant example of autoimmunity is the condition of individuals having type $1$ diabetes. In autoimmune disease, the immune system destroys the cells within the pancreas, which produce insulin.
Though there are more than $80$different autoimmune diseases, $14$ are the foremost common ones, namely type $1$ diabetes, pernicious anemia, celiac disease, rheumatoid arthritis, Grave’s disease, Hashimoto’s thyroiditis, Myasthenia gravis, autoimmune vasculitis, psoriasis, multiple sclerosis, systemic lupus erythematosus, inflammatory bowel disease, Addison’s disease, and Sjogren’s syndrome.
For many autoimmune diseases, the initial symptoms are very similar, which are as follows:

Achy muscles
Fatigue
Redness and swelling
Fever in low-grade
Trouble in concentration
Loss of hair
Skin rashes
Individual diseases also exhibit their own symptoms. In type $1$ diabetes, extreme thirst, weight loss, and fatigue are the symptoms. Belly pain, bloating, and diarrhea are the symptoms displayed in inflammatory bowel disease.
Depending on the disease and symptoms, a visit to a specialist is generally recommended. A positive result from the antinuclear antigen test (ANA) can be indicative of an autoimmune disorder. The symptoms and other tests for the confirmation of diagnosis.

Note:
In the case of psoriasis and rheumatoid arthritis, symptoms may come and go. The onset of symptoms is termed autoimmune flare-up and then the period when the symptoms go away is defined as remission. General symptoms like swelling, muscle aches, and redness can be signs of an autoimmune disease, but the symptoms may come and go over time.