What are the characteristics of urticaria in a skin physical examination (PE) and how is it typically managed?

Characteristics of Urticaria in Skin Physical Examination and Management

Urticaria presents as short-lived, itchy, raised wheals with or without angioedema that typically resolve within 2-24 hours without leaving a trace. 1, 2

Physical Examination Findings of Urticaria

Classic Urticarial Wheals

• Raised, edematous plaques with central swelling of various sizes 1
• Surrounding erythema (redness) around the central swelling 1
• Intensely pruritic (itchy) lesions, occasionally with burning sensations 3
• Transient nature - typically resolve within 2-24 hours without scarring 1, 2
• May appear anywhere on the body 1

Red Rash with Central Clearing

• This pattern represents the classic appearance of urticarial wheals as they evolve 1
• Central area may appear paler than the erythematous border 1
• The central clearing distinguishes urticaria from other dermatological conditions 1

Angioedema (when present)

• Deeper swelling involving lower dermis and subcutaneous tissue 4
• Often affects mucous membranes (lips, eyelids, genitalia) 1
• May cause pain or burning rather than itching 4
• Slower to resolve - can persist up to 72 hours 1, 4

Distinguishing Features from Other Conditions

• Duration of individual lesions: urticarial wheals typically last 2-24 hours, while urticarial vasculitis lesions persist for days 1
• Physical urticaria wheals generally resolve within an hour (except delayed pressure urticaria) 1
• Lack of residual hyperpigmentation or bruising (unlike urticarial vasculitis) 1
• Lesional skin biopsy can confirm urticarial vasculitis if suspected 1

Types of Urticaria to Consider in Examination

Ordinary Urticaria

• Spontaneous wheals appearing anywhere on the body 1
• May be acute (<6 weeks), chronic (≥6 weeks), or episodic (recurrent) 1

Physical Urticarias

• Triggered reproducibly by specific physical stimuli 1
• Types include:
  • Dermatographism (triggered by stroking or scratching skin) 5
  • Cold contact urticaria (cold exposure) 1
  • Cholinergic urticaria (small wheals triggered by sweating) 1, 5
  • Delayed pressure urticaria (pressure areas develop wheals 2-6 hours later) 1
  • Solar urticaria (sunlight exposure) 5
  • Aquagenic urticaria (water contact) 5

Contact Urticaria

• Occurs only when eliciting substance is absorbed through skin/mucosa 1
• Never spontaneous, always related to specific contact 1

Management Approach

First-Line Treatment

• Non-sedating second-generation H1 antihistamines are the mainstay of treatment 3
• Can be titrated to higher than standard doses for better control 3
• Examples include cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine 1

Second-Line Options

• First-generation antihistamines (with caution due to sedation) 3
• H2 receptor antagonists may be added in resistant cases 2
• Brief corticosteroid bursts for severe exacerbations 2, 3

Additional Considerations

• Identify and avoid specific triggers when possible 1
• Minimize non-specific aggravating factors (overheating, stress, alcohol) 1
• Avoid NSAIDs and aspirin in sensitive patients 1
• Cooling antipruritic lotions (calamine, 1% menthol in aqueous cream) can provide symptomatic relief 1

For Severe/Refractory Cases

• Omalizumab, cyclosporine, or leukotriene receptor antagonists may be considered 2
• For life-threatening angioedema with respiratory involvement, immediate epinephrine administration is crucial 2, 4

Prognosis

• Acute urticaria typically resolves within days to weeks 3
• More than half of patients with chronic urticaria experience resolution or improvement within one year 3
• Physical urticarias may be more persistent 1