Treatment of Purpura on Hands, Feet, and Trunk in Adults with Allergies
Immediate Diagnostic Priority
The first critical step is to determine whether this represents Hand, Foot, and Mouth Disease (HFMD), allergic contact dermatitis, drug-induced purpura, or cutaneous vasculitis, as this fundamentally changes management and corticosteroid use may be contraindicated or even harmful in HFMD. 1, 2
Key Distinguishing Features to Assess:
- Recent viral prodrome with fever and oral lesions suggests HFMD (vesicular lesions in mouth, hands, feet) 1
- New medication exposure within past 2-4 weeks suggests drug-induced purpura or papular-purpuric gloves and socks syndrome 3, 4
- New clothing or textile contact suggests purpuric allergic contact dermatitis to textile dyes (Disperse Blue 106/124 most common) 5
- Palpable purpura with systemic symptoms suggests cutaneous vasculitis requiring skin biopsy 6
- Recent shellfish or food exposure in allergic patient may trigger IgA-mediated vasculitis 7
Treatment Algorithm Based on Diagnosis
If HFMD is Suspected (Vesicular Lesions, Fever, Oral Involvement):
Do NOT use corticosteroids—they suppress the necessary immune response for viral clearance and may increase risk of severe complications and death. 2
Supportive care only:
- Oral analgesics (acetaminophen or NSAIDs) for pain and fever relief for limited duration 1, 2
- For oral lesions: benzydamine hydrochloride oral rinse/spray every 3 hours before eating 1, 2
- For skin lesions: intensive moisturizing with urea-containing creams, avoid friction and heat 1, 2
- Zinc oxide as protective barrier for itchy lesions 1, 2
- For open sores on feet: daily washing with careful drying, cushioned footwear, avoid walking barefoot 1
- Monitor for secondary bacterial infection (increased redness, warmth, purulent drainage) 1
If Drug-Induced Purpura is Suspected:
Immediately discontinue the suspected offending medication (common culprits: trimethoprim/sulfamethoxazole, NSAIDs, antibiotics). 3, 4
Treatment approach:
- Systemic corticosteroids are useful when drug withdrawal alone is insufficient 6
- Consider prednisone 40-50 mg daily initially, then taper based on response 8, 6
- Alternative agents if corticosteroids contraindicated: dapsone or colchicine 6
- Most cases are self-limited after drug discontinuation 6, 3
If Allergic Contact Dermatitis to Textiles is Suspected:
Remove contact with suspected textile allergen and perform patch testing with Textile Color & Finish Series to identify specific dye/resin. 5
Management:
- Potent topical corticosteroids to affected areas 5
- Systemic corticosteroids if extensive involvement 6
- Avoid re-exposure to identified allergen (most commonly Disperse Blue 106, Disperse Blue 124, Disperse Blue 85, ethyleneurea melamine formaldehyde) 5
If Cutaneous Vasculitis is Suspected (Palpable Purpura):
Obtain skin biopsy to confirm leukocytoclastic vasculitis before initiating systemic therapy. 6, 7
Treatment based on severity:
- Mild, self-limited cases: Observation alone, as many are idiopathic and resolve spontaneously 6
- Moderate cases: Systemic corticosteroids (prednisone 40-60 mg daily initially) 6, 7
- Severe cases with renal involvement or thrombotic microangiopathy: Consider plasma exchange in addition to high-dose corticosteroids (methylprednisolone 500 mg IV daily for 3 days) 7
- Alternative agents: Dapsone or colchicine if corticosteroids contraindicated 6
Critical Pitfalls to Avoid
- Never prescribe corticosteroids empirically without ruling out HFMD first—this can be life-threatening 2
- Do not use topical antiseptic or antimicrobial dressings routinely for HFMD foot lesions—not recommended for wound healing 1
- Avoid aspirin and NSAIDs in aspirin-sensitive urticaria patients—may worsen symptoms 9
- Do not soak feet in footbaths with open lesions—induces maceration and worsens sores 1