Allergies are characterized by an inflammatory response to allergens , local or systemic. Local symptoms are typical:
Nose: swelling of the nasal mucous membrane and drain the liquid sneezing ( allergic rhinitis ).
Eyes: redness and itching of the conjunctiva ( allergic conjunctivitis ). Almost always it is a phenomenon accompanying allergic rhinitis.
Lower airways: irritation, bronchoconstriction, attacks' s asthma .
Skin: allergic dermatitis such as eczema , hives , atopic dermatitis (partially) and contact dermatitis .
Body problems: diarrhea or constipation, sexual and relational problems, and depending on the severity of regurgitation can cause serious heart problems.
The systemic allergic response is also called " anaphylaxis ": depending on the level of severity, can cause skin reactions, bronchoconstriction, edema , hypotension up to anaphylactic shock which may cause coma , sometimes lethal.
The antibodies responsible for allergic reactions are the " IgE ", also called" reagin ". They are usually present in all individuals. The assay is performed with a blood test called PRIST (Paper Radio Immuno Sorbent Test). A high level of IgE in the blood directed towards allergy but can be found in people who are not allergic. The main test for the diagnosis of allergy skin test is the " prick test ". With such an investigation is made to contact a small amount of allergen with the skin of the patient gently milled with the aid of special hands by tiny bit. If the patient has IgE antibodies active against a specific allergen, you will see a reaction with itching swelling ( wheal ) at the substance to which the patient is allergic. Other investigations are utlilizzate RAST (Radio Allergo Sorbent Test) that seeks IgE directly into the bloodstream. The test triggering organ in which it causes the allergy experimentally by exposing the patient to the suspected allergen is commonly used for the diagnosis of allergic rhinitis and conjunctivitis.