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Urticaria is a diverse group of conditions characterized by transient, intensely itchy, raised wheals (hives) and/or deeper swelling (angioedema). Individual wheals last less than 24 hours and may migrate or appear in crops.
What will the patient tell you? (History)
What will the patient tell you? (History)
Key Subtypes and Triggers:
Acute Urticaria:
Duration / Key Feature: <6 weeks duration.
Common Triggers/Associations: Viral illness (common in children), new foods (nuts, shellfish), drugs (antibiotics, NSAIDs).
Chronic Spontaneous Urticaria (CSU)
Duration / Key Feature: >6 weeks duration; daily or almost daily.
Common Triggers/Associations: No clear trigger in most cases. Often associated with autoimmunity (e.g., thyroid disease).
Contact Urticaria
Duration / Key Feature: Wheals occur minutes after direct skin contact
Common Triggers/Associations: Latex, raw foods, cosmetics, occupational chemicals. Immediate reactions suggest IgE mediated allergy.
Urticaria Pigmentosa (Mastocytosis)
Duration / Key Feature: Chronic mast cell accumulation; lesions last >24 hours.
Common Triggers/Associations: Heat, friction, alcohol, NSAIDs, emotional stress. Darier sign (rubbing the lesion to whealing ).
Solar Urticaria
Duration / Key Feature: Wheals occur minutes after sun/UV exposure.
Common Triggers/Associations: Visible light or UV radiation.
Crucial Note for Darker Skin Tones:
Patients may not see or describe "redness." They often report "burning," "heat," or "swelling." Chronic rubbing can lead to hyperpigmented, lichenified areas, and the active hives often leave behind dark marks (Post-inflammatory Hyperpigmentation).
What will it look like? (Examination)
General Findings:
Wheals: Well-circumscribed, oedematous (swollen), raised areas, often with central pallor (whiteness).
Angioedema: Deeper, non-pitting swelling, typically of the eyelids, lips, or tongue.
Duration: Individual lesions resolve within 24 hours (except in Urticaria Pigmentosa).
Key Examination Nuances in Darker Skin Tones:
Wheal Appearance: Wheals may appear skin-colored, hyperpigmented, or violaceous rather than red.
Post-inflammatory Hyperpigmentation (PIH): Darkening is common and may resemble other pigmentary disorders (e.g., eczema or contact dermatitis), confusing the diagnosis.
Urticaria Pigmentosa: Presents as brown macules/patches that, when stroked, demonstrate a darker swelling (the Darier sign).
Image Sourced From Allergy Asthma Network
Image Sourced From Derm Net
How can you help? (Treatment)
The primary treatment for all types of urticaria is avoidance of triggers and daily antihistamines.
1. First-Line for ALL Urticaria:
Non-sedating second-generation antihistamines (e.g., Cetirizine, Loratadine, Fexofenadine) taken daily.
For Chronic Urticaria, the dose may be increased up to 4 times the standard dose if initial response is inadequate.
2. Acute Urticaria:
Trigger Avoidance: Identify and avoid the likely cause (food, drug, infection).
Cold compresses for symptomatic relief.
Short course of oral steroids (3–5 days) only if the flare is severe. Avoid NSAIDs, as they can worsen hives.
3. Chronic Spontaneous Urticaria (CSU):
Follows a stepwise approach:
Step 1 & 2: Standard-dose to Up-dosed antihistamines (up to 4 times).
Step 3 (Refractory): Add-on therapies are needed:
Omalizumab (an anti-IgE biologic) is the next line.
Cyclosporine may be used for highly refractory cases under specialist care.
4. Subtype-Specific Management:
Contact Urticaria: Strict avoidance of the trigger substance. If IgE-mediated (e.g., latex), assess for anaphylaxis risk and prescribe an EpiPen if needed.
Solar Urticaria: Strict sun avoidance, broad-spectrum SPF. Phototherapy (UV hardening) may be used for desensitization.
Urticaria Pigmentosa: Avoid triggers (heat, friction, NSAIDs, alcohol). Children often improve with age. Severe cases require specialist referral (EpiPen, systemic therapy).
Darker Skin Tones – Treatment Considerations:
Hyperpigmentation: Counsel patients that the resulting PIH may persist for weeks or months after the active hives have cleared.
Topical Steroids: Use high-potency topical steroids with caution, especially on the face, to avoid the risk of hypopigmentation (lightening).
PIH Management (Adjunctive): Once the active hives are controlled, sun protection is essential. Topical agents like Azelaic acid or retinoids may be used to help fade the PIH.
Sources
Skinsight – Hives (Urticaria): https://skinsight.com/skin-conditions/urticaria-hives/
DermNet NZ – Urticaria – Overview: https://dermnetnz.org/topics/urticaria-an-overview
NCBI Bookshelf / StatPearls – Chronic Urticaria: https://www.ncbi.nlm.nih.gov/books/NBK555910/
NCBI Bookshelf / StatPearls – Urticaria Pigmentosa: https://www.ncbi.nlm.nih.gov/books/NBK482503/
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