What is the treatment for a rash/hives that has covered the body for approximately 1 week?

Treatment of Generalized Hives/Urticaria Lasting One Week

For a widespread urticarial rash persisting for one week, start oral non-sedating antihistamines at standard doses (cetirizine 10 mg or loratadine 10 mg daily), add topical corticosteroids for symptomatic areas, and if symptoms are severe or not improving within 2 weeks, escalate to oral prednisone 0.5-1 mg/kg/day for a short course. 1

Initial Treatment Approach

First-Line Therapy: Antihistamines

• Begin with oral non-sedating H1-antihistamines such as cetirizine 10 mg daily or loratadine 10 mg daily 2
• These should be taken regularly on a scheduled basis, not just as needed after hives appear 3
• For nighttime pruritus, add sedating antihistamines like hydroxyzine 10-25 mg at bedtime 2
• Non-sedating antihistamines (cetirizine, loratadine, fexofenadine) are preferred for daytime use to avoid impairment 2, 4

Adjunctive Topical Treatment

• Apply topical corticosteroids to affected areas: Class I (clobetasol propionate, betamethasone dipropionate) for body areas and Class V/VI (hydrocortisone 2.5%, desonide) for facial involvement 2
• Use emollients with fragrance-free, cream or ointment-based moisturizers to prevent skin drying 2
• Avoid alcohol-containing lotions or gels 2

Escalation for Persistent or Severe Symptoms

When to Escalate (After 2 Weeks or If Severe)

If the rash covers >30% body surface area, causes significant functional impairment, or fails to improve after 2 weeks of antihistamines: 2

• Add oral corticosteroids: prednisone 0.5-1 mg/kg/day (typically 40 mg daily for adults) 1, 3
• Continue until rash resolves to mild severity, then taper 2
• The steroid course should be brief (typically 3-10 days) to minimize toxicity 5
• Important caveat: If symptoms recur after steroid taper (as in your case), this suggests chronic urticaria requiring a different long-term strategy 1

For Recurrent Urticaria After Steroid Taper

• Do not restart prolonged corticosteroids due to cumulative toxicity 5
• Instead, maximize antihistamine dosing: increase to 2-4 times the standard dose (e.g., cetirizine 20-40 mg daily) 6, 5
• Studies show response rates improve progressively with 2,3, and 4 tablets daily compared to single dosing 6
• This high-dose antihistamine approach is effective in approximately 50% of patients 6

Key Clinical Considerations

Rule Out Serious Causes

• Assess for systemic symptoms suggesting anaphylaxis (throat tightness, difficulty breathing, wheezing, hypotension) which would require epinephrine 2
• Check CBC with differential and comprehensive metabolic panel if considering systemic involvement 2
• Consider dermatology referral if no improvement after 2 weeks of appropriate treatment 2, 1

Common Pitfalls to Avoid

• Don't use antihistamines only "as needed" - they must be taken regularly for chronic urticaria 3
• Don't continue oral corticosteroids long-term - toxicity is dose and time dependent 5
• Don't assume first-generation antihistamines work faster - studies show oral fexofenadine has similar onset to diphenhydramine without sedation 4
• Avoid hot showers and excessive soap use which can worsen symptoms 2

If Antihistamines Fail at High Doses

For the approximately 50% of patients who remain refractory to high-dose antihistamines: 6, 5

• Next step is omalizumab 300 mg monthly (effective in 70% of antihistamine-refractory cases) 5
• Leukotriene antagonists and H2-blockers are no longer recommended as they add minimal benefit 6, 5
• Cyclosporine is reserved for those failing both antihistamines and omalizumab (effective in 65-70%) 5

Reassessment Timeline

• Reassess after 2 weeks of any treatment change 2
• If worsening or no improvement, escalate therapy and consider specialist referral 2