Allergy patients can experience four primary types of allergic reactions:
- Anaphylactic – The most common type of allergic reaction that causes the body to release chemicals like histamine, leading to inflammation and swelling.
- Cytotoxic – A rare form of allergic reaction where antibodies and antigens bind together on the antigen’s cell surfaces, causing damage to healthy cells and leading to dangerous complications.
- Immune-complex – A rare form of allergic reaction where antibodies and antigens bind together and harm tissues and organs, leading to autoimmune diseases and complications.
- Cell-mediated – A rare form of allergic reaction where white blood cells are activated rather than antibodies, resulting in delayed reactions following exposure.
Allergies vary in severity and type from person to person. In a group of ten people who are all sensitive to the same or similar allergens, it’s possible to observe a range of responses since allergies manifest in different ways depending on the individual’s immune system and immune sensitivity.
What Causes an Allergic Reaction?
The immune system is responsible for the allergic reactions the body develops when exposed to bothersome triggers. When the immune system encounters an allergen that it is sensitive to, it treats the substance the same way it would a dangerous invader, like a virus or bacterial infection. The immune system’s goal is to flush the allergen out as quickly as possible, even if it’s non-threatening or harmless.
Some people have immune systems that are not responsive to allergens, while others suffer from having immune systems that are moderately to extremely reactive to allergens.
In most cases, it’s the protein in the substance that bothers the immune system. In rarer instances, it’s the polysaccharides or other polymers that the immune system reacts to, triggering an allergic reaction.
Common allergens include:
- Pollen
- Pet dander
- Dust mites
- Mold spores
- Insect venom
- Latex
- Certain foods
- Medications
Four Types of Allergic Reactions
Most people think of congestion, excessive sneezing, watery eyes, skin irritation, and similar symptoms when they envision an allergic reaction. However, there is actually a much wider range of reactions people can experience depending on the type of response their immune systems have to allergen exposure.
An allergy patient can have a reaction that is classified into one of four categories: types I (anaphylactic), II (cytotoxic), III (immune-complex), and IV (cell-mediated).
Type I – Anaphylactic Reaction
The most common of all allergic reactions, type I allergic reactions (or anaphylactic reactions), occur when the immune system triggers the release of chemicals, including histamine, as well as the antibody immunoglobin E (IgE). These chains of reaction cause certain areas of the body to swell and develop inflammation.
Allergens that can cause anaphylactic reactions include:
- Pollen
- Dust mites
- Mold spores
- Food proteins
- Insect stings or bites
Symptoms of anaphylactic reactions include:
- Airway narrowing
- Breathing difficulties
- Facial swelling
- Nausea and vomiting
- Runny nose
- Scratchy throat
- Skin rashes and hives
- Watery or itchy eyes
As the name suggests, type I allergic reactions can lead to anaphylaxis, or anaphylactic shock, if the body reacts severely enough to an allergy trigger.
Should you or someone you know develop anaphylaxis after exposure, call 911 or seek medical attention immediately.
Type II – Cytotoxic Reaction
Cytotoxic reactions occur when the immune system encounters an antigen, or trigger, and releases antibodies immunoglobulin G (IgG) and immunoglobulin M (IgM) in response. The antigens and antibodies bind together on the surface of the antigen’s cells, but because the binding process is toxic and destructive, it damages surrounding healthy cells.
Cytotoxic reactions are involved in a number of autoimmune diseases like:
- Autoimmune hemolytic anemia
- Graves’ Disease
- Immune thrombocytopenia
- Myasthenia gravis
- Pernicious anemia
- Polymyositis
Among others.
The causes of a cytotoxic reaction can vary but include:
- Taking certain medications
- Penicillin and other antibiotics
- Methyldopa
- Thiazide diuretics
- Undergoing a blood transfusion with the wrong blood type
- Having certain autoimmune diseases or conditions
Symptoms of cytotoxic reactions vary based on the reason for the response or the autoimmune disease that the patient suffers from. However, some symptoms a patient can experience include:
- Anemia
- Jaundice
- Weight loss
- Muscle weakness
- Fatigue
- General ill feeling
- Irritability
Type III – Immune-complex Reactions
Immune-complex reactions, sometimes called immunocomplex reactions, occur when soluble antigens and antibodies IgG and IgM bind and settle on tissues and organs rather than surrounding healthy cells. As the antibodies and antigens react to one another, proteins in the blood that help eliminate pathogens are activated to help the antibodies fight off the antigens, a process called the complement system. When activated, these proteins lead to inflammation, which damages or even kills healthy cells and tissues.
Immune-complex reactions can range from acute to chronic, as well as minor to severe.
Immune-complex reactions are involved in a number of autoimmune diseases like:
- Rheumatoid arthritis
- Serum sickness
- Systemic lupus erythematosus
- Glomerulonephritis
- Arthus reaction
- Idiopathic polyarteritis
- Goodpasture’s syndrome
Among others.
The causes of an immune-complex reaction can vary but include:
- Taking certain medications
- Exposure to mold spores
- Exposure to too many allergens at once
- Having certain autoimmune diseases or conditions
Symptoms of immune-complex reactions vary based on the reason for the response or the autoimmune disease that the patient suffers from. However, some symptoms a patient can experience include:
- Joint pain
- Joint swelling
- Rash development
- Organ damage
- Blood flow issues
- Fever
Type IV – Cell-Mediated Reactions
Cell-mediated allergic reactions do not occur because of the release of antibodies, like types I-III do. Instead, a reaction occurs when T cells (thymus cells) interact with the present antigen. After identifying an allergen, the immune system sends the necessary T cells to attack and eliminate the antigen. During the attack, inflammation occurs, along with other reactions, leading to symptoms for the patient.
Because it takes much longer for T cells to find and attack an antigen in the body, cell-mediated reactions are delayed by 18 to 24 hours, even 48 or 72 hours, so the allergy patient does not experience symptoms until about a day after exposure.
Chronic asthma and many skin allergies result in cell-mediated reactions. The allergens that can lead to a cell-mediated reaction for some patients include:
- Pollen
- Pet dander
- Dust
- Dust mites
- Mold spores
- Certain foods
- Metals, like nickel
- Poison ivy
- Certain antibiotics
- Certain cosmetics
- Detergents
- Household chemicals
- Latex
Symptoms of cell-mediated reactions can vary, but symptoms often include:
- Skin irritation
- Skin inflammation
- Rash development
- Breathing difficulties
No matter which type of allergic reaction you experience, Langford Allergy has your treatment or management solution.
Dr. Langford, Dr. Mathew, and our team of allergy specialists understand the various types of allergies patients can suffer from, as well as the appropriate treatment options to help manage allergies and find relief. We create individualized and effective treatment and management plans that promote safety, no matter what allergic reactions you experience.
Schedule an allergy appointment today: 478-787-4728
Langford Allergy delivers allergy, asthma, and immunodeficiency care to patients throughout Middle Georgia, including:
- Bonaire, GA
- Byron, GA
- Forsyth, GA
- Fort Valley, GA
- Gray, GA
- Macon, GA
- Milledgeville, GA
- Perry, GA
- Warner Robins, GA
And other surrounding areas.
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