According to the symptoms you describe and their duration, you are probably experiencing chronic-recedivant urticaria. All types of urticaria are due to the liberation of the chemical substance 'histamine' from a type of cell called a 'mastocyte' in the skin. There are 4 types of urticaria, each with different mechanisms that can lead to histamine liberation:
1. Immunological. This type of urticaria is provoked by an allergen that causes the creation of specific IgE-antibodies upon first contact with the body. However, there is no urticaria present during the first contact. This type of urticaria is acquired. During the second contact with the allergen (and every contact thereafter), the IgE-antibodies bind the allergen to the mastocytes’ surface. This binding with the mastocytes causes the liberation of histamine and the appearance of urticaria;
2. Pharmacological. In this type of urticaria there are no immunological mechanisms involved. That’s why it is called a 'pseudo-allergy', or 'idiosyncrasy'. In these cases, an urticaria can occur during first contact with an allergen. It is believed that idiosyncrasies are due to a genetic defect in the metabolism of particular substances (inborn allergy). These allergens then directly stimulate the mastocytes to liberate histamine. Some medicines like aspirin can cause this type of urticaria.
3. Physical urticaria. This type of urticaria is due to a physical factor and there are several more common types: urticaria factita (caused by friction); urticaria pressione (due to a strong, localized pressure); cholinergic urticaria (provoked by physical effort, swelling or emotional excitement); urticaria frigore/calore (occurs when the body is exposed to cold or warm), and photogenic urticaria (caused by sunlight).
4. Idiopathic urticaria. These types of urticaria have a completely unknown etiology and they occur during infections, during various thyroid and gastrointestinal disorders, and simultaneously with malignant tumors.
Diagnostic of chronic urticaria includes several standard procedures to identify the provoker:
1. Excluding physical provokers with thermal and mechanic provocative tests;
2. Exposition tests to exclude various possible allergens;
3. Examination of the feces for Candida and parasite eggs;
4. Searching for an infective focus (sinuses, tooth, stomach, intestines).
Therapy includes mainly antihistamines, while corticosteroids and adrenalin are used for urgent cases. It is most important to identify and eliminate the provoker when treating urticaria. Continue working with your doctors. Now that you are more informed, you can request the diagnostic examinations to identify the true cause of the hives.
