Uritcaria & Angioedema

What to consider in Primary Care before referring:

General Comments

• This is now believed to be an autoimmune process
• In the vast majority of patients with urticaria no underlying trigger factor or associated disease is found and the condition is self-limiting.
• Prick tests and RAST tests are not useful as a screening test of potential allergens in chronic ordinary urticaria.
• Food allergy is usually obvious and trigger factors such a crustaceans, fish and nuts can be easily identified.
• Contact urticaria is generally suggested by the history and can be confirmed by contact urticaria tests that are different to patch tests, which have no place in the investigation of urticaria..
• Physical urticarias including:
  Dermagraphism
  Cholinergicurticaria
  Cold urticaria
  Solarurticaria
  Pressure urticaria
  can usually be identified on history.

• Urticaria may follow non-specific infections, hepatitis, streptococcal infections, campylobacter and parasitic infestation.

• Rarely it may be a symptom of an underlying systemic disease such as thyroid disease or connective tissue disease.

Management in Primary Care & advice for self-care

• Explain the condition to the patient and reassure that it is benign and usually self-limiting.
• Minimise:
  Overheating
  Alcohol
  Caffeine
  Stress
• Review drug history - both prescribed and non-prescribed, as many drugs have been reported to cause Urticaria such as penicillins, ACE inhibitors, statins and NSAID’s, in particular aspirin.
• Additionally opiates and NSAID’s may exacerbate existing urticaria.
• Exclude:
  C1 Esterase Deficiency (If angioedema is the only sign)
  Insect bites

Treatment in primary care

Antihistamines

• There is little to choose between different antihistamines but individuals may vary in their response to different agents.

• Sedative or non-sedative antihistamine choice depends on the need for sedation.

• Many antihistamines block histamine wheals and itching but do not suppress the rash completely.

• Use continuous medication if attacks occur regularly.

• Use fast acting antihistamines as required for sporadic attacks.

• If there is no response to one agent after four weeks, try a second and then a third agent.

• In some cases of severe acute urticaria such as a Penicillin reaction, a short reducing course of Prednisolone starting at 30mgs – 40mgs od may be useful.

• Systemic steroids should not be used in chronic urticaria.

Summary of non-sedating and low-sedating antihistamines

Note: In pregnancy it is suggested that the long established antihistamines be used