Urticaria

Urticaria
Chronic Urticaria is common and extremely difficult condition.Chronic urticaria presents in a variety of presentation.About 5 % are shown to be Reactive to the food allergens.5% may have urticarial vasculitis.

Physical urticaria is seen in about 35%-40 %, aprox. 50 % have so called Idiopathic Urticaria.

 Epidemiological data available is scare. In UK about 1% of the population will suffer from urticaria during their lifetime. Out of this appox. 25 % of the patients would be of chronic urticaria.

Physical Urticaria: In this most striking is dermographism. A useful procedure in confirming the diagnosis of dermographism is challenge test with a  calibrated dermographometer, which measures the pressure being applied to the skin.Other common physical urticarias are cold urticaria, cholinergic urticaria and solar urticaria. Cold urticaria can be tested by applying ice to the skin, cholinergic urticaria can be seen by exercising the patient or bathing in warm water and solar urticaria can be tested by solar simulator lamp.  
Cold urticaria can be tested by applying ice to the skin  
Solar urticaria can be tested by solar simulator lamp.Patients with physical urticaria need no firther investigations. The patients shold be informed of the condition for which the average time course of 2-3 years, and during this time the main therapeutic approach is to cover the patient with H1 antihistamine. Very little is known about the pathogenesis of the physical urticaria.  
Urticarial Vasculitis:In this the duration of the wheals is important. If the wheals last longer than the 24 hrs, the patient almost certainly has urticarial vasculitis. Staining of the the skin after fading of the wheals is another clue. Itching is not a major problem with this type of urticaria. The lesions are more likely to be tender and painful.  The diagnosis of this type of urticaria is confirmed with skin biopsy. Another very important point to remember in this is that urticarial vasculitis may be a marker for serious systemic diseases involving kidneys, lung or cardiovascular system. It may be associated with hepatitis B or C. It may be first sign of autoimmune connective tissue diseases such as Sjogren’s syndromeSystemic Lupus or Rheumatoid Arthritis. This condition is difficult to treat. Among the drugs useful are Dapsone, Colchicine, Indomethacin, Phentoxiphylline, Azathioprine, Corticosteroids.Food Allergens:A small proportion of the patients of chronic urticaria are allergic to food additives such as preservatives like Tartrazine and Sodium Benzoate, coloring agents and various antioxidants.

Parasitic infestations:

May also produce urticaria especially in under developed countries.

Chronic Idiopathic Urticaria:

Autoimmune phenomenon appears to play part in  in about 30-50% of the patients of Chronic idiopathic urticaria. Such patients have functional autoantibodies reacting with IgE receptor on the mast cells.

Management 

Aggravating factors such as alcohol consumption, intercurrent infection, vigrous exercise and psychological stress should be kept in mind to understand why urticaria is at times worse.

Antihistamine Treatment – Antihistamines such as Fexofenadine,  Loratadine and Certizine.

In patients uncontrolled with antihistamines, a short course oral steroids may have to be given. In some patients Cyclosporin for a period of 3 months may have to be given.

 Skin Diseases