Signs and Symptoms

• A slight female predominance
• Can affect any age although 50% present between the ages of 20 and 40
• 25% of patients have an atopic background
• Symptoms
  • Although the condition may persist for several months, or in some cases years, individual lesions generally last between 30 minutes and 4 hours
  • Can have additional elements of physical urticaria such as dermographism or delayed pressure urticaria
• Angioedema will affect some patients but is rarely life threatening
• Natural history: 50% of patients with spontaneous urticaria can expect to be clear in six months, but some persist for years
• Rapid appearance of raised erythematous very itchy skin swellings "wheals"

Differential Diagnoses

Individual lesions disappear within 24 hours and if not consider:

• erythema multiforme
• urticarial vasculitis (lesions can last for days and leave bruising)
• erysipelas
• if female of child bearing age - polymorphic eruption of pregnancy

Acute urticarial

• Idiopathic
• Viral infections
• Physical – touch, pressure, hot, cold, solar, water, chemicals, cosmetics
• Drugs – aspirin, opioids, NSAIDs, antibiotics, ACE inhibitors, statins, diuretics
• Allergic – foods, infections

Chronic urticaria

• Idiopathic most common
  • Chronic idiopathic urticaria is not an allergy but more because of irritable mast cells that degranulate with little or no provocation
  • Often in 20-40 year old females
  • Often a response to emotional stress or hormonal changes
  • Usually burns out after several months to a couple of years
• Physical – touch, pressure, hot, cold, solar, water
• Drugs – aspirin, opioids, NSAIDs, antibiotics, ACE inhibitors, statins, diuretics
• Allergic – foods, infections Secondary to other disease – SLE, viral hepatitis, hyperthyroidism, lymphoma, infection
• Auto-immune urticaria

Blood tests

• Check TFT and autoantibodies - patients found to have significant titres of thyroid autoantibodies should have their TFT re-checked every six months as they are at increased risk of developing thyroid disease

H.pylori status

• Check in patients with recalcitrant urticaria and who also have dyspepsia - urticaria may improve in some patients following H.pylori eradication

Other tests

• In general, patients will not benefit from RAST or skin prick tests as an allergic cause is highly unlikely - a RAST test against a specific food may sometimes be used to disprove a theory, such that a negative result would make it very unlikely that any given food is responsible for the reaction

There is no place for patch testing

Formulary, Chapter 13. Skin: Management of urticaria

Referral criteria

• Diagnostic uncertainty (e.g. suspected drug rash or vasculitis)
• Severe disease unresponsive to primary care management (secondary care treatments include cyclosporine, oral steroids and omalzumab)

Patient Information

• Acute urticaria lasts less than 6 weeks, chronic is 6 weeks or longer
• Acute urticaria
• Chronic urticaria

Evidence

North and East Devon - formulary - Skin

The Primary Care Dermatology Society

Pathway Group

This guideline has been signed off on behalf of NHS Devon.

Publication date: 30 January 2017