They're abnormal immune responses - by definition, an allergy is an inappropriate response to a foreign substance. After all, it's not known as an 'allergy' when people's immune systems attack harmful pathogens, despite the body mounting somewhat similar immune responses.
There are four different types of hypersensitivities. Type I Hypersensitivities are mostly allergies and they are exaggerated, misdirected expression of immune responses to an allergen (antigen). The severity of allergies can range from atopy (local allergy such as hay fever or asthma) or anaphylaxis (a violent and potentially fatal reaction that leads to narrowing of the bronchial airways). Foods, drugs, pollen and bee stings can trigger these reactions and this kind of sensitivity can be transferable to normal people through serum antibody.
Regulatory T cells (Treg) suppress the action of other T cells. This inhibits immune responses to self-antigens, aiming to prevent the immune system from attacking normal self cells.
Immunology is the study of the immune system and applies to animals the same way as it does to humans. Animals can have allergies, autoimmune disorders (arthritis, depressed immune systems, etc.) that need to be treated so that the animal can live a more normal life.
No. Autoimmune disorders are those in which your bodies immune system recognizes a certain type of your own tissue as foreign tissue and activates an immune response to destroy what it believes foreign. Your regular immune responses are still functional to fight normal infection.
Normally, immune complexes are not detected in the blood.
Yes, seasonal allergies are no different from 'normal' allergies.
LUCY
A person with allergies is generally understood to have an immune system that over-reacts to normal and inocuous materials, such as pollen. The "allergy shot" is an injected solution containing a very dilute and small amount of these materials. The idea behind allergy shots is to continuously expose the immune system to very low levels of the material so that the immune system learns to "tolerate" the material and the person will stop having allergy symptoms. Generally the person will need to be on allergy shots for the rest of his/her life - without constant low-level stimulation, the immune system tends to lose its tolerance and the allergy symptoms return.
Allergies can improve over time, although they often worsen.Learning to recognize and avoid allergy-provoking situations allows most people with allergies to lead normal lives.
Headaches can happen anytime during whole day or night. So it can happen during allergies too.
Normal cells are unable to destroy viral invaders because viruses hijack the cellular machinery to replicate themselves, making it difficult for the immune system to detect them. Additionally, viruses often employ various mechanisms to evade immune responses, such as altering their surface proteins or inhibiting the host's antiviral pathways. As a result, the immune system may not recognize the infected cell as a threat until after significant viral replication occurs.
Disease-causing agents like viruses, bacteria, and worms are called pathogens. They can invade the body and cause illnesses by disrupting normal bodily functions and triggering immune responses.