There are a number of different forms of urticaria and they can be grouped as spontaneous urticaria, physical urticaria and other types of urticaria.
The forms of spontaneous urticaria are:
- Acute spontaneous urticaria: Hives are formed and fade away after hours or days, at the latest after six weeks.
- Chronic spontaneous urticaria: Hives or angioedemata are formed; the symptoms persist for more than six weeks.
The forms of physical urticaria are:
- Urticaria factitia: Rubbing, scratching, or scrubbing the skin.
- Cold urticaria: Contact between the skin and cold.
- Heat urticaria: Contact between the skin and warmth/heat.
- Solar urticaria: UV light or sunlight
- Pressure urticaria: Pressure
Other forms of urticaria include:
- Aquagenic urticaria: Contact between the skin and water.
- Cholinergic urticaria: Raised temperatures (for example due to hot baths).
- Contact urticaria: Contact between the skin and certain substances.
- Exercise-induced urticaria/anaphylaxis: Physical strain.
Chronic spontaneous urticaria (CSU) can be diagnosed with a detailed patient history. A GP will usually ask a patient to keep a symptom diary to record any potential triggers in order to exclude or confirm a diagnosis of CSU. It is important to record the onset, duration and course of CSU. The duration of the individual wheals and rash should also be recorded accurately. Any occurrence of angioedema should be noted. Further tests may include evaluations of the skin, blood and urine. If initial treatment is ineffective, GPs should refer patients to see a specialist dermatologist or immunologist for further treatment.
Until recently, antihistamines were the only licensed therapy option for people living with CSU. Medical guidelines recommend doctors increase the dosage up to four times the licensed dose; however 40% of people with CSU still do not experience relief from symptoms from this increased dose. Non sedating antihistamines are usually prescribed in the first instance, but sedating antihistamines may be prescribed, particularly at night to help with night time itch. However, patients may need to face the additional issues of dealing with fatigue and restriction on daily activities (such as driving), due to sedating treatment.
In the absence of alternative licensed treatments, guidelines suggest second-line therapy with drugs such as corticosteroids and montelukast. Third-line therapy includes treatments which act upon the immune system, such as ciclosporin, mycophenolate and methotrexate. Although not specifically licensed or designed to treat the condition, they may be successful in a percentage of patients. Recently, omalizumab, a drug that modifies the immune response, has received a licence for the treatment of CSU following publication of positive phase 3 trial data. The Specialised Dermatology Clinical Reference Group will make recommendations to NHS England on the inclusion of this treatment in a commissioning policy.