Urticaria

Disclaimer

These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

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Aim

To guide PCH ED staff with the assessment and management of urticaria.

Background

  • Urticaria, is a common disorder, with a prevalence of 3 - 4% in childhood
  • A typical urticarial lesion is an intensely pruritic, erythematous plaque
  • Urticaria is sometimes accompanied by angioedema, which is swelling deeper in the skin
  • Urticaria is not normally painful
  • Acute urticaria usually settles within hours, but may last up to 6 weeks.

Common causes

  • Infection - 80% of acute urticaria is related to viral, bacterial, and parasitic infections
  • Allergic reactions to medications
  • Foods - allergic reactions to foods can cause urticaria, typically within 30 minutes of ingestion. Milk, egg, peanuts, tree nuts, soy, and wheat are the most common foods to cause generalised urticaria in children
  • Insect stings and bites
  • Medications.

Differential diagnosis

Non-pruritic conditions

  • Viral exanthems.

Pruritic conditions

  • Atopic dermatitis
  • Contact dermatitis
  • Scabies
  • Drug eruptions
  • Insect bites
  • Erythema multiforme - the lesions may be painful or pruritic and distributed symmetrically on the extensor surfaces of the extremities (particularly the palms and soles). Individual lesions last several days, unlike urticaria. There may be accompanying fever and malaise.

Management

  • Approximately two-thirds of cases of new-onset urticaria will be self-limited and resolve spontaneously.

H1 antihistamines

Cetirizine

  • 1 to 2 years old, the oral dose is 2.5 mg once daily
  • 2 to 6 years old, the oral dose is 5 mg once daily
  • > 6 years old, the oral dose is 10mg once daily.

Loratadine

  • 1 to 2 years, oral dose is 2.5mg once daily
  • > 2 years and < 30kg, oral dose is 5mg once daily
  • > 30kg, oral dose is 10mg once daily.

Second-generation agents

  • These drugs are minimally sedating, are essentially free of the anticholinergic effects that can complicate use of first-generation agents.

Gluccocorticoids

A brief course of systemic steroids for 3-5 days may be added to antihistamine therapy to control persistent and severe symptoms but only in the setting of extreme distress as acute urticarial can last 6 weeks and may result in excessive use of oral steroids.

Bibliography

  1. Bingham CO (2015) New Onset Urticaria. UpToDate. Accessed at www.uptodate.com.
  2. AMH Children’s Dosing Companion (2015) Australian Medicines Handbook Pty Ltd.
  3. Nelson Textbook of Pediatrics: 20th Edition Robert M. Kliegman, Bonita M.D. Stanton, Joseph St. Geme, Nina F Schor Publisher: Elsevier 



Endorsed by:  Director, Emergency Department   Date:  Aug 2017


 Review date:   Aug 2020


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