What types of allergies are there?
There are different allergic diseases depending on where the inflammatory reaction occurs.
Rhinitis, conjunctivitis, asthma, atopic dermatitis, eczema and urticaria, are the most common allergic diseases.
If the reaction is on the skin, it may be Atopic Dermatitis, also called eczema. This involves reddened, itchy skin and tends to appear in childhood. It may also be Urticaria, characterised by the appearance of welts on the skin, which are also itchy. Sometimes, it may be accompanied by swelling of the lips and eyelids. This is called Angio-oedema.
If the reaction is on the skin, it is Rhinitis, which features itching, nasal obstruction, postnasal drip and sneezing. In most cases, it also affects the eyes and causes Conjunctivitis with itching, reddening and watering of the eyes. Rhinitis that appears exclusively in spring or summer is called seasonal rhinitis as opposed to perennial rhinitis, whose symptoms occur throughout the year.
When an allergic reaction occurs in the bronchi, these constrict, which hinders the passage of air and produces a characteristic sound, called wheezing. At the same time, the patient experiences trouble breathing (dyspnoea), coughing and chest tightness. These are symptoms of Allergic Asthma. Most of the time, patients with asthma also have rhinitis.
When patients ingest a food to which they have a food allergy, an inflammatory reaction occurs in their gastrointestinal system: Gastroenteritis, which may lead to the onset of abdominal pain, vomiting and diarrhoea. At the same timeUrticariamay appear as a result of absorbing the food in question.
There are particularly serious cases in which there is a massive release of inflammatory substances throughout the body and the individual develops an all-over reaction called ANAPHYLAXIS.
Symptoms of anaphylaxis include: a feeling of heat, reddening, tingling in the mouth and urticaria with itching. Other symptoms may be a feeling of dizziness, dyspnoea, throat tightness, pain/cramps and/or vomiting and diarrhoea.
Anaphylactic Shockoccurs if anaphylaxis compromises the heart and circulatory system and leads to very low blood pressure with loss of consciousness and shock.
Anaphylaxis is particularly common in people with allergies to bee and wasp venom when they are stung by these insects. It is also more common in people with drug and latex allergies.
The most characteristic symptoms of allergic reactions are: Nasal itching, watering of the eyes, conjunctivitis, sneezing, postnasal drip and nasal obstruction, coughing, difficulty breathing, reddened skin, and swelling.