All About Urticaria

Urticaria (hives) is derived from the Latin word “urtica” which means “to burn”. They are characterised by wheals which are superficial skin-coloured or pale skin swellings, usually surrounded by erythema (redness) that lasts anything from a few minutes to 24 hours. Usually, they are very itchy and sometimes, it may have a burning sensation. Angioedema is deeper swelling within the skin or mucous membranes and can be skin-coloured or red. It resolves within 72 hours. Angioedema may be itchy or painful but is often asymptomatic. In around 30% patients of urticaria, attacks often recur for months or years.

Types of urticaria

The classification is based upon duration.

• Acute urticaria (< 6 weeks duration) – Usually it is gone within hours to days.
• Chronic urticaria (> 6 weeks duration) – Daily or episodic weals are common. Chronic urticaria may be spontaneous or inducible. Both types may co-exist.

Who gets urticaria?

One in five children or adults has an episode of acute urticaria during their lifetime. It is more common in atopics and affects all races and genders. Chronic spontaneous urticaria affects 0.5–2% of the population.

Causes

Hives occur when certain cells release histamine and other chemicals into your bloodstream. Doctors often can’t identify the reason for chronic hives or why acute hives sometimes turn into a long-term problem. The skin reaction may be triggered by:

• Medications: Hives may be caused or flared up by certain medicines. Most commonly pain medicines like aspirin, other nonsteroidal anti-inflammatory drugs, opioids, ACE inhibitors, oral contraceptives, and alcohol.
• Contact With Allergens: Contact urticaria occurs within 30-60 minutes of contact with an allergen like latex (especially in health care workers), plants, animals (eg, caterpillars, dander), medications, and food (eg, fish, garlic, onions, tomato).
• Neurological factors: An Italian study reported an association between CU and fibromyalgia. The authors proposed that CU is a consequence of fibromyalgia-neurogenic skin inflammation.
• Thyroid Disease: In some cases, chronic hives may be related to an underlying illness, such as thyroid disease.
• Insects or parasites
• Infection
• Food allergy: Usually milk, egg, peanut, shellfish.
• Vaccination
• Bee or wasp stings
• Scratching
• Heat or cold
• Stress
• Sunlight
• Exercise
• Alcohol or food
• Pressure on the skin, as from a tight waistband

Hives and stress

One factor that can make hives worse, is emotional stress. A study in 2005 linked stressful life events, low family support, and insomnia with hives. Chronic stress can lead to dysregulation of various inflammatory mediators and exacerbate the underlying disease. In other words, when a person is stressed, any inflammatory reactions are likely to be more severe in a person who is susceptible to a reaction. In this way, hives can be linked to stress.

Infections

Hives has been reported to be associated with a number of infections including Streptococcus, Mycoplasma, Helicobacter pylori, Mycobacterium tuberculosis, Herpes simplex virus, and Hepatitis B virus. Fungal infections such as onychomycosis, tinea pedis and candida have been considered as possible associations. Chronic Hives has been associated with parasitic infestations such as strongyloidiasis, giardiasis and amoebiasis.

Infections are more likely to cause acute urticaria in children where it accounts for a higher percentage of cases as compared to adults. Sometimes dental infections can also lead to hives.

Chronic Spontaneous Urticaria

Chronic spontaneous urticaria (CSU) is mainly idiopathic (cause unknown). An autoimmune cause is likely. CSU has also been associated with:

• Chronic underlying infection, such as Helicobacter pylori, bowel parasites.
• Chronic autoimmune diseases.

What are the clinical features of urticaria?

The wheals can be a few millimetres or several centimetres in diameter, coloured white or red, with or without a red flare. Some of the characteristics of hives are:

• Each weal may last from a few minutes to several hours and may change shape.
• The weals can occur in any part of the body and tend to occur in different areas throughout the duration of the condition.
• Itching, which may be severe.
• A tendency for signs and symptoms to flare with triggers such as heat, exercise and stress.
• A tendency for signs and symptoms to persist for more than six weeks and to recur frequently and unpredictably, sometimes for months or years.
• Painful swelling (angioedema) – This occurs in 30% of the cases and commonly affects the face (especially eyelids and around the mouth), hands, feet and genitalia. It may involve tongue, or inside the throat.

Complications

Anaphylaxis is a severe allergic reaction that can affect the whole body. Immediate medical attention is needed if there is:

• Nausea and vomiting
• Swelling of the lining of the mouth, tongue, lips, and throat, causing breathing difficulty.
• Rapid heartbeat
• Faintness or lightheadedness
• Unexpectedly abrupt feeling of intense anxiety
• Cold and clammy skin

When to see a doctor

Consult a skin specialist if you develop acute or chronic urticaria. The dermatologist will usually prescribe a non-sedative newer generation H1 antihistamine to control the hives as well as any further counselling and treatment according to the severity and characteristics of the condition. Patient education is also a very important part of the treatment for hives.

Investigations

In spite of extensive laboratory investigations, 50% of cases of chronic hives remain idiopathic which means that it does not have any specific cause. An elevated WBC count or elevated ESR may suggest the possibility of an underlying systemic disease and eosinophilia should prompt a search for parasitic diseases. Screening test for thyroid function and antithyroid peroxidase and antithyroglobulin antibodies may be carried out in candidate patients. Positive autologous serum skin test (ASST) suggests an underlying autoimmune mechanism. In vitro ‘basophil histamine release assay’ is currently the gold standard for detecting functional autoantibodies.

Diagnosis

Usually, the diagnosis depends on the patient’s history and the clinical features on skin examination. Your skin doctor will do a physical exam and ask you a number of questions to try to understand what might be causing your signs and symptoms. He or she may also ask you to keep a diary to keep track of:

• Your medical history including any pre-existing conditions or recent infections etc.
• Your activities.
• Any medications, herbal remedies or supplements you take.
• What you eat and drink.
• Where hives appear and how long it takes a to fade.
• Whether your hives come with painful swelling.

If your physical exam and medical history suggest your hives are caused by an underlying problem, your doctor may have you undergo testing, such as blood tests or skin tests.

Read about some common myths and FAQs about hives.

To know more about the treatment of Urticaria, check out – Urticaria Treatment.