Urticaria or hives can be a nuisance to the sufferer, at times producing serious consequences, and a challenge to the treating physician. It is more of a detective work to find out the exact cause of urticaria, and, most of the time, laboratory investigations including the allergy tests are inconclusive.
What are the Different Types of Urticaria?
There are different types of urticaria or hives, depending upon the duration and severity of clinical features.
- Acute Urticaria. Acute onset and remain or recur for duration less than 6 weeks.
- Dermographism. Itchy wheals appearing after stroking the skin and fading after 30 minutes.
- Chronic Urticaria. Urticaria of more than 6 week’s duration, continuous, or, more commonly, is recurring.
- Angioedema. A medical emergency, when the wheals of urticaria affect the deep dermis and subcutaneous tissue rather than the upper dermis in normal urticaria. This can cause lethal effects when swelling occurs in the airway system cutting off oxygen to the lungs.
What are Wheals?
Wheals are the characteristic eruptions seen in urticaria caused by accumulation of fluid leaked from the blood vessels due to release of histamine and other chemical mediators from the mast cells in response to an allergic response to a variety of allergens. The edema or swelling mainly affects the upper dermal layers in dermographism and normal urticaria and deep dermis and subcutaneous tissue in angioedema.
What is the Cause of Urticaria?
It is told that anything under the sun, including the sun, can cause urticaria. The common causes of urticaria or hives include food and food additives, medications, toxins from insect bites, plants and infectious agents, chemicals, water, sun, physical agents like pressure, friction, sweating, cold, heat, endocrinal abnormalities like hyperthyroidism, malignancies like leukemia, lymphomas, colon cancer etc, contact allergy, inhalants like dust or pollen, stress, and, finally, the chronic idiopathic urticaria where no cause could be identified even after extensive investigations.
Laboratory Tests in Urticaria
In acute urticaria, routine tests are not required, as treatment is mainly symptomatic. Extensive history taking and making a list of things done, eaten or came into contact with before the hives started will help in eliminating the cause in some cases.
In chronic urticaria, the whole systems should be investigated to rule out any internal causes. Complete blood counts, urine and stool tests and liver function, kidney function and thyroid function tests are mandatory. Allergy tests may help in finding the cause of the urticaria in a rare number of cases. Other systemic tests should complement the detailed history and physical examinations undertaken.
How to Treat Urticaria
The treatment of urticaria is with short and long acting antihistamines, steroids and treatment or avoidance of the precipitating cause.
- Make a list of things that you have done, eaten or come in contact to before you got the hives.
- Try avoiding the suspected agents, as far as possible.
- When you get the attacks, take a short acting antihistamine like Benadryl 1 at night and/or Cetrizine 10 mg 1 in the morning.
- These antihistamines can cause sedation; hence special care should be taken while driving.
- Some severe and generalized cases may require oral steroids.
- If this first line of treatment does not help, you will have to see a dermatologist to have primary investigations to rule out other causes.
- Signs of angioedema, like swelling of the eyelids, face, lips and difficulty in breathing call for immediate visit to the casualty or ER. Adrenaline is life saving in such situations, and can only be administered in a hospital setting.
Urticaria is a challenge to any physician because finding and eliminating the cause of the hives is an important part in the management of the disease.
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Disclaimer
The information given in this article is for educational purpose only so that patients are aware of the options available. No diagnosis should be made or treatment undertaken without first consulting your doctor. If you do so, the author or suite101 will not be responsible for any consequences. The images provided are for illustration purpose only.
Hanish Babu - Dr.Hanish Babu, MD is a dermatologist and a feature writer on Suite101.com with more than 200 articles related to skin diseases on the ...
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