Dermatology Search
Dermatology Dermatology
urticaria
URTICARIA
Urticaria is characterized by sudden appearance of wheals and/or angioedema.
The intensity of the pruritus varies but may be severe enough to disrupt sleep, work or school.
It is classified acute if the urticaria has been present for <6 weeks and chronic if >6 weeks. A specific cause is more likely to be identified in acute cases.
It can be triggered by immunological or nonimmunological mechanism.

Diagnosis

  • Diagnosis is based on patient’s history & physical exam

Classification

  • Urticaria is classified as acute or chronic
    • A specific cause is more likely to be identified in acute cases
  • Can be triggered by immunological or non-immunological mechanism

Acute Urticaria

  • Lesions occurring <6 wk in duration & usually w/o angioedema
  • More common in children & young adults & tends to have a triggering event

Chronic Urticaria

  • More common in adults (3rd & 4th decades of life), symptoms last >6 wk

Chronic Spontaneous Urticaria

  • Urticaria that has spontaneously recurred at least 2x/wk for >6 wk w/ unknown causes

Inducible Urticaria

  • Cold contact
  • Delayed pressure
  • Heat contact
  • Symptomatic dermographism
    • Daily lesions & recurrent episodic lesions are not differentiated
  • Solar urticaria
  • Vibratory angioedema
  • Aquagenic urticaria
  • Cholinergic urticaria
  • Contact urticaria

Autoimmune Chronic Spontaneous Urticaria (ACU)

  • Proposed gold standard for diagnosis of ACU (combination of all 3 parameters):
    • Positive bioassay [eg basophil histamine release assay (BHRA), basophil activation marker expression] AND
    • Positive autoreactivity [eg positive autologous serum skin test (ASST)] AND
    • Positive immunoassay for specific IgG autoantibodies against FcεRIα and/or anti-IgE

Physical Examination

Look for typical lesions of urticaria

  • Wheals which typically are fleeting, lasting w/in 1-24 hr, have a central swelling of variable size surrounded by erythema & associated w/ itching, sometimes burning sensation
  • Angioedema characterized by a sudden evident swelling of the lower dermis & subcutis which may last up to 72 hr
  • Lesions may appear on any part of the body

Stroke the arm to test for dermographism/dermatographism

  • Discontinue antihistamine therapy for at least 2-3 days, immunosuppressive therapy for at least a wk
RECOMMENDED DIAGNOSTIC TESTS FOR URTICARIA SUBTYPES
Subtype Test Extended Diagnostic Tests
Acute spontaneous Presence of wheals/pruritus None
Chronic idiopathic spontaneous Differential blood count & ESR or C-reactive protein (CRP), omission of suspected drugs (NSAIDs, ACE inhibitors, antibiotics) Test for: Infectious diseases, type 1 allergy, autoantibodies, thyroid hormones, skin test, pseudoallergen-free diet for 3 wk, lesional skin biopsy*, autologous serum skin test
Autoimmune chronic spontaneous Autoreactivity, functional bioassay & immunoassay Differential blood count, ESR/CRP cryoproteins
Cold contact Cold provocation & threshold test (eg ice cubes, cold water) Differential blood count, ESR/CRP cryoproteins, rule out other diseases/infections
Delayed pressure Pressure test (0.2-1.5 kg/cm2 for 10 & 20 min) & threshold test None
Heat contact Heat provocation & threshold test (eg warm water) None
Solar UV & visible light of different wavelengths Rule out other light-induced dermatoses
Demographic Test by stroking the arm Differential blood count, ESR/CRP cryoproteins
Aquagenic Apply wet cloths set at body temperature for 20 min None
Cholinergic Exercise & hot bath provocation None
Contact Cutaneous provocation test, prick/patch test (see results after 20 min) None
Exercise-induced History of urticaria after exercise, appearing w/ or w/o food intake but not after a hot bath None
Modified from: EAACI/GA2LEN/EDF/WAO guidelines: management of urticaria, 2013.
*Lesional skin biopsy indicated for lesions lasting for >36 hr

Assess disease activity of chronic spontaneous urticaria

  • Several guidelines recommend using the Urticaria Activity Score (UAS7) system in assessing disease severity
    • Summation of scores of symptoms during a 7-day period
  • 1 = mild wheals (<20 wheals w/in 24 hr) + mild (nontroublesome) pruritus
  • 2 = moderate wheals (20-50 wheals w/in 24 hr) + moderate (troublesome but does not interfere w/ daily activities or sleep) pruritus
  • 3 = intense wheals (>50 wheals w/in 24 hr or large confluent wheals) + intense (severely troublesome, interferes w/ daily activities & sleep) pruritus
Editor's Recommendations
Most Read Articles
Psoriasis-affected BSA helps identify patients at risk of diabetes
15 Jan 2018
Body surface area (BSA) affected by psoriasis can be measured to target diabetes prevention efforts for patients with psoriasis, a recent study suggests.
Fern extract a potential adjunct therapy for melasma in Asians
Pearl Toh, 14 Apr 2018
Taking the oral extract product of the fern Polypodium leucotomos (PLE) on top of the standard topical hydroquinone cream and sunscreen reduces the severity of melasma to a greater extent compared with the standard treatment alone in Asian patients, a pilot study has shown.
Hydrochlorothiazide use may increase nonmelanoma skin cancer risk
Stephen Padilla, 18 Apr 2018
High use of hydrochlorothiazide (HCTZ) appears to significantly increase the risk of nonmelanoma skin cancer (NMSC), particularly squamous cell carcinoma (SCC), suggests a recent study. Use of other diuretic and antihypertensive medications does not appear to be linked to NMSC.
Patient-taken swabs to diagnose gonorrhoea in women
01 Jun 2013

An article by the same team in Leeds (see above) addresses the question of swabs for the diagnosis of gonorrhoea in the cohort of 3,973 women.