Urticaria

Urticaria (also known as hives) is an intensely itchy outbreak of raised bumps, and usually comes on suddenly – usually with no obvious triggers.

Overview

The name urticaria is derived from the Latin name of the European stinging nettle – urtica dioica, and it is sometimes referred to as ‘nettle rash,’ as the presentation can be similar to the result of contact with the prickly plant.



There are several different forms of urticaria, and it affects 1 in 5 people at some point in their lives.



Symptoms of Urticaria

Urticaria can appear anywhere on the body and presents as very itchy reddish-pink or white raised bumps, which are known as wheals (sometimes spelt ‘weals’.) Wheals are often round, or ring-shaped, but can also appear as lines.

An outbreak of urticaria can last anywhere from a few minutes to several months – although most tend to resolve within 24 hours.

There are two different classifications of the condition, which are based on the duration:

  • Acute urticaria, which lasts for less than six weeks and often disappears in a matter of hours, or at the most, days.
  • Chronic urticaria, which lasts more than six weeks, and may result in the presentation of daily, or ‘episodic’ wheals.

Chronic urticaria may be spontaneous, or it can be what’s called inducible – meaning that it arises due to an external stimulus. An outbreak of chronic urticaria may be spontaneous and also affected by external factors at the same time.

There are multiple forms of inducible urticaria. They include:

Where itchy wheals appear on the skin appear as lines after friction, like rubbing. The itching may be aggravated by environmental factors, such as heat.
Where itchy wheals are triggered by exposure to cold, including rain, wind or cold water. Swimming in cold water can cause severe wheals and fainting, and should be avoided. Patients with the condition should advise medical staff before undergoing any surgery.
In this rare condition, redness, itching and wheals appear immediately after exposure to sunlight, and disappear less than an hour after getting out of the sun.
This is an extremely rare condition in which small wheals appear when the skin makes contact with water. It normally presents on the upper part of the body.
This presents where pressure has been applied to the skin – for example from tight clothes. In many cases, swelling develops several hours after contact, and the condition can be very painful and last longer.
This presents as a result of sweating, so factors like heat, strenuous activity, exercise, emotional stress and eating spicy food can trigger an outbreak. Small itchy bumps with varying degrees of redness appear very rapidly. They usually affect the upper part of the body, but can be widespread. While wheals last for less than an hour, in severe cases, they may join together, forming larger swellings. Antihistamine tablets are often helpful, but it’s best to speak with a doctor before taking these routinely.
Where physical contact with animals, plants, foods or chemicals cause wheals to appear at the site of contact. While most reactions are mild, they can be severe in people with allergies – for example, to nuts or rubber. Some common allergens are eggs; nuts; citrus fruits; latex; and pets.

While sometimes the source of an urticaria outbreak are more obvious, many times there is no specific cause. An infection, like a cold virus; or skin contact with an allergen may trigger the onset of the condition.

Causes of Urticaria

Urticaria is caused by the release of histamine from the mast cells in the skin. While sometimes the source of an urticaria outbreak are more obvious, many times there is no specific cause. An infection, like a cold virus; or skin contact with an allergen may trigger the onset of the condition.

Common allergens that result in urticaria are:

  • Contact with animals
  • Sun exposure
  • Medicine
  • Insect bites and stings
  • Foods – commonly, shellfish, nuts, apples and peaches

In babies, cow’s milk can frequently trigger the onset of urticaria.

If it is suspected that a medicine has triggered urticaria, either you or your doctor should report the symptom to the MHRA Yellow Card scheme. While the majority of medicines contain ingredients that might cause urticaria, painkillers, antibiotics, blood products and vaccinations are often responsible.

Some people with chronic health conditions, such as thyroid disease or pernicious anaemia, may present with urticaria when the immune system directs an attack against the body’s own tissues.

In people with chronic spontaneous urticaria, the mast cells are triggered to release histamine by factors in the blood, such as antibodies, and this is known as autoimmunity. Tests for autoimmunity are not widely available, however the presence of the condition does not change the way the resulting urticaria is treated.

If foods are triggering urticaria, it may be helpful to keep a food diary to log reactions and track the presence of colouring agents or preservatives. This may limit individuals’ outbreaks to specific foods, and be helpful to show doctors.

Urticaria may be made worse by lifestyle or environmental factors. While triggers vary, tight clothing, hot temperatures and drinking alcohol or caffeine are common factors that can worsen an outbreak.

Taking over-the-counter antihistamines may lessen the symptoms or severity of the urticaria, but not eliminate the condition completely.

It is not advisable to combine multiple types of antihistamine before checking first with a doctor or pharmacist, as there can be contraindications. In chronic cases, patients should consult their GP to discuss additional treatment options for urticaria.

It is essential to seek urgent medical advice if you are experiencing problems breathing or swallowing during an outbreak of urticaria. 

Treatment of Urticaria at Derma

Your appointment with the dermatologist will begin with analysis of the affected area, and together you will discuss your medical history, before a course of treatment for urticaria is recommended.

In some patients with a suspected allergen, it may be necessary to confirm the trigger by testing a small amount of blood. This may be referred to as a ‘scratch test,’ and is conducted in order to detect the presence of antibodies in the bloodstream.

Prescription antihistamines or other treatments for urticaria may be prescribed in addition to standard over-the-counter treatments and can improve results. The dermatologist will let you know whether it is beneficial to continue with over-the-counter treatment, or if it is advisable to stop. Urticaria may also be improved with tablets or creams prescribed by the doctor.

If other methods are not effective, you may be a candidate for treatment that works to suppress the immune system.

The dermatologist will discuss the latest and most effective treatments and explain all potential side-effects, to enable you to select the best option for you.

Depending on the treatment and the severity of your condition, further tests and follow-up appointments may be required to manage your treatment.

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