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4 allergy types
Division of the allergic reactions into 4 types
Certain reaction types are typical of the allergic illnesses. One distinguishes four types after the different reaction mechanism and after the period of time between allergen contact and the occurrence of symptoms. These reaction ways are, an important differentiation criterion this also is co-deciding in favor of the treatment of an allergy.
Type 1: Allergies of the immediately type, anaphylactic reaction
Rapid and often intense reactions of the immediately type. Approximately 90 per cent of all allergies are allergies of immediately type. The symptoms appear few minutes until hours after the contact with the allergen and speak in the extreme case as a hay fever, exanthemas or asthma, for example as an anaphylactic shock. It is reactions of the antigen IgE type and therefore around the "classic" reaction way at the typical hay fever with antibodies of this. The inclination towards the development of multiple allergies of the immediately type is called atopy.
Typical allergic illnesses are:
Hay fever
Animal hair allergy
Insect sting allergies
Latex allergies
House dust mite allergies
Food allergy
Allergies against medicines (local anesthetics, antibiotics)
Allergic asthma
Nettle rash
Quincke edema
Anaphylactic shock
Particularly intense reactions have to be expected from Atopic, which increased a genetic predisposition for one IgE allergens have production at contact with one. Coordinating points for the allergic reaction are the mast cells. Mast cells are special white blood corpuscles. You belong to the defense cells which are formed in the bone marrow. Mast cells are in the loose connective tissue of all organs, also in the area of the skin and in the blood vessels. Small vesicles, these with so-called mediators or messenger substances, are especially in the mast cells histamine is filled.
Antibodies which fasten themselves on the mast cells produces at a contact with an allergen be IgE. These antibodies can capture and neutralize an allergen molecule. This also calls itself antigen-antibody reaction. At a first contact with the allergen only some become fastened IgE antibody covered to the neutralization this one on the mast cell. This reaction step calls itself sensitization.
At the next contact with the same antigen the allergic reaction then comes to light. Antibody celebration pinned the on a massive scale on the mast cells this can be on one single mast cell between 10,000 and 50,000, capture the allergen which serves as a trigger for an excessive distribution of histamine. By the intense reaction the mast cell bursts open really.
The symptoms are triggered by histamine. Histamine and other inflammation mediators are the reason that the blood vessels widen strongly. Fluid leaves within seconds until minutes and it comes to the formation of the typical edemas and wheals. The blood pressure sinks. The persons affected suffer from pruritus, red and regular nose, eye tears and dyspnea.
These reactions are locally frequently restricted. An example of it is the hay fever or the nettle rash. How this is the case at an anaphylactic shock expansion of the allergic reaction to the organism can do at one a life-threatening condition enter. Nausea is the reaction in addition to the symptoms mentioned above by strong blood pressure drop, a narrowing of the bronchial tubes and tumescences and edemas in this area of the larynx indicated, in addition spasm appears, possible and strong hot flusheses open.
The delayed reactions of the type I which are caused by a delayed release or neoformation of mediators/messenger substances have to be distinguished by the immediately type mentioned here clinically, however. The latency time is here up to 6 hours. The same is the working mechanism as in the case of the immediate reaction entering within less seconds until minutes, the symptoms, however, appear only after a longer time interval.
Type 2: Allergies of the cytotoxic type
At the second form of the allergic reaction the cells are damaged themselves. Therefore it is called also cytotoxic reaction (cell = zyto). Specific antibodies get bound directly to the surface of endogenous cells at this reaction. By this process the endogenous cell has become even an antigen which must be fought. The IgG and IgM antibodies take a key position. You combine with the xenobiotic which lies on the body cell. In addition, becomes the complement system activated, part of the nonspecific immune defense. It consists dissolve of different plasma proteins (egg-white substances in the blood plasma) which attack body foreign egg-white and so-called phagocytes here curls, cell walls. It therefore comes to the cytolysis of endogenous cells and to the inflammation reinforcement at this allergic reaction. The results of this cell destroying activity can be various: Anemias (anemia), formation of bubbles of the skin, thyroid hypofunction or solid kidney corpuscle inflammation and lung hemorrhage (Goodpasture syndrome).
Typical illnesses of the type 2 are:
Hemolytic transfusion reactions
Rhesus incompatibility with newborn childs
autoimmune hemolytic anemias
Myasthenia grave accent
Agranulocytosis
A carries antibodies blood group incompatibility (against blood group A into blood group B himself and reversely).
Type 3: Allergies of the immune complex type
The allergic reaction of the type 3 is marked by the formation of immune complexes (allergen+antibody). Under certain conditions at antigen excess increase-limbed complexes form from allergens and antibodies, so-called soluble immune complexes which spread out with blood and Lymphstrom in the whole body and get stuck in the capillaries (kidneys, skin, joints).
The immune complexes then lead bleedings and necrosis about a strong activation of the complementsytem (component of the nonspecific immune system) to an intense inflammation with edemas, vasculitis, vessel thrombosis. This leads to a dissolving of the immune complexes, however, also damages the surrounding tissue. What to this "accumulation" leads, isn't cleared till now. However, it is known that the IgG antibody is essentially involved in it.
The immune system is not able always to neutralize the immune complexes completely. A deposit of the "supernumerary" immune complexes is typical of this form of the allergic reaction in certain tissues. They then lead to allergic inflammation reactions there. However, the symptoms of an allergy don't immediately appear. It already needs a couple of hours or also days until allergic reactions let themselves be seen. These at the immune complex type triggered reactions can be limited locally (classic example: Arthus reaction) or generalizedly (classic example: Serum sickness).
Typical illnesses, these to this belong to type 3 are and others:
Vasculitis (vascular inflammation)
Serum sickness
Alveolitis inflammation (of the pulmonaries alveoli), farmer's lung
Nephritis (inflammation of the kidneys)
Arthritis (inflammations of the joints)
Type 4: Cellular immunoreaction, late reaction type
T of play are role are exclusively the T lymphocytes involved The antibodies Don in The allergic reaction of a The type 4. here at the immune reaction '. The T lymphocytes are specialized white blood corpuscles and are part of the specific cellular defense. For this reason the allergic reaction is called also cellular immunoreaction by the type 4.
Allergenic or body foreign substances are taken up by body cells as 2 described into type and activate specific T lymphocytes=sensitization phase. The T lymphocytes can recognise and fight these cells. Being able to be substances (cytokines) which lure macrophages (phagocytes) released but also lead to a damage done to the surrounding tissue. At the place of the antigen contact it comes, on to a cell infiltrate the this one hits one can feel as solid dot-like place.
Without this first contact it cannot come to a type IV allergy. The T cells remember a defense action carried out once. If they get in contact with the same allergen once again, then it can trigger intense allergic reactions. The (redouble-) activation of the T lymphocytes and the cell immigration needs, however, time so that symptoms appear not immediately but first 12 to 72 hours after the allergen contact.
Typical of this form of the allergy is:
Transplant rejection
Contact allergies e.g. at nickel allergy
Tuberculin reaction (TB test)
Drug exanthemas
After an organ transplantation the transplanted organ is frequently repealed.
This rejection reaction is also an allergic immunoreaction of the type 4.
These informations may be considered a substitute for a piece of medical advice in no case. The content of health-illness.com doesn't can and may be put into any case to make diagnoses or carry out self medical treatment independently.
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