In a patient with new onset CSU, what investigations should be done?

Associate Professor Emek Kocatürk discusses the investigations that should be carried out when seeing a patient with new onset chronic spontaneous urticaria.

Answer

CSU presents as wheals and/or angioedema which usually last for less than 24 hours and resolve without leaving a mark. These symptoms occur for 6 weeks or more.1

The diagnosis of CSU is usually made clinically. Not all possible causative factors need to be investigated in all patients, however, a thorough history should be taken as the first step:1

  • onset of disease
  • frequency of attacks
  • provoking factors
  • diurnal variation
  • shape, size and distribution of wheals
  • angioedema
  • pain, itch, burning, fever
  • induction by physical stimulation
  • gastrointestinal symptoms
  • correlation to food and menstrual cycle
  • previous response to therapy and diagnostic results
  • family history
  • allergies
  • psychosomatic/psychiatric history
  • surgical implantations
  • drugs
  • lifestyle factors (work, smoking, hobbies, quality of life)

Following the patient history, a physical examination should be performed. This should include a diagnostic provocation test including drug, food and physical tests where indicated by the patient’s history. All subsequent diagnostic steps will depend on patient history and on the nature of the urticaria subtype.1

EAACI Guidelines recommend only very limited routine diagnostic measures in chronic spontaneous urticaria.1

Routine

  • C-reactive protein (CRP)/erythrocyte sedimentation rate (ESR)
  • differential blood cell count

Extended

  • infectious diseases
  • Ttpe I allergy
  • functional autoantibodies
  • thyroid hormones
  • physical tests
  • low-pseudoallergen diet
  • autologous serum skin test (ASST)

 

Frequent spontaneous urticaria subtypes - recommended diagnostic tests1
Subtype Routine diagnostics tests (recommended) Extended diagnostic program (based on history)

Acute spontaneous urticaria

None

None (unless strongly indicated by patient history, e.g., allergy)

Chronic spontaneous urticaria

Differential blood count. ESR or CRP. Omission of suspected drugs (e.g., NSAID)

Test for (in no preferred order): Infectious diseases e.g. Helicobacter pylori, Type 1 allergy, functional autoantibodies, thyroid hormones and autoantibodies, skin tests including physical tests, low-pseudoallergen diet for 3 weeks, ASST, lesional skin biopsy

 

Inducible urticaria subtypes - recommended diagnostic tests1
Subtype Routine diagnostics tests (recommended) Extended diagnostic program (based on history)

Cold urticaria

Cold provocation and threshold test (ice cube, cold water, cold wind)

None

Heat urticaria

Heat provocation and threshold test

None

Solar urticaria

UV and visible light of different wavelengths

Rule out other light-induced dermatoses

Symptomatic dermographism

Elicit dermographism and threshold test (dermatographometer)

Differential blood count, ESR or CRP

Vibratory angioedema

Test with, for example, laboratory vortex

None

Aquagenic urticaria

Wet cloth at body temperature applied for 20 minutes

None

Cholinergic urticaria

Exercise and hot bath provocation

None

Contact urticaria

Cutaneous provocation test. Skin tests with immediate readings (e.g., prick test)

None

 

  • Emek Kocatürk

    Dr Emek Kocatürk received her MD degree from Hacettepe University School of Medicine, Ankara, Turkey in 1999.

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  • References:

    1. Zuberbier T, Aberer W, Asero R, Bindslev-Jensen C, Brzoza Z, Canonica GW, et al.  The EAACI/GA2LEN/EDF/WAO Guideline for the definition, classification, diagnosis, and management of urticaria: the 2013 revision and update.  Allergy. 2014;69(7):868-87.

     

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