Diagnosis: Urticaria (Hives)

Treatment Algorithm

Step 1 - First line (ALL cases)

• Goldman-Cecil Medicine, p. 4904

Step 2 - If inadequate control after 2-4 weeks (or sooner if intolerable)

• Add an H2 antagonist (famotidine 20 mg twice daily or cimetidine 400 mg twice daily) - useful since 15% of skin histamine receptors are H2
• Add a leukotriene receptor antagonist - montelukast 10 mg/day
• Add a first-generation antihistamine at bedtime (e.g., hydroxyzine 10-25 mg, diphenhydramine 25-50 mg)

If Severe Acute Urticaria (with or without angioedema)

• Diphenhydramine 25-50 mg PO or 10-50 mg IV/IM q4-6h (max 400 mg/24h)
• Corticosteroids - short course only:
  • Prednisone 0.5-1 mg/kg/day (up to 30-50 mg/day) tapered over 1-2 weeks
  • OR Triamcinolone 40-60 mg IM single dose
  • OR Dexamethasone 4-20 mg IV/IM for severe cases
• Steroids should be used as rescue medication, not long-term, due to rebound and side effects - Dermatology 2-Vol Set, p. 500

Step 3 - Refractory Chronic Urticaria (specialist referral)

• Omalizumab (anti-IgE monoclonal antibody) 150-300 mg SC monthly - strong evidence, well tolerated
• Ciclosporin 3 mg/kg/day for 8-16 weeks (under specialist supervision)
• Other options with weaker evidence: dapsone, hydroxychloroquine, methotrexate, narrow-band UVB, IVIG

If Anaphylaxis (throat/tongue swelling, wheezing, hypotension)

• Epinephrine 0.3-0.5 mg IM (1:1000) thigh - immediately
• IV fluids, oxygen, IV diphenhydramine + IV famotidine, IV methylprednisolone
• This is a medical emergency - Goldman-Cecil, p. 4914-4920

Special Populations

• Pregnancy: Loratadine or cetirizine are preferred (former FDA category B); avoid hydroxyzine near parturition
• Children: Rarely need step 3 therapies; cetirizine or loratadine weight-adjusted
• Breastfeeding: Loratadine and cetirizine are compatible

Practical Points for This Patient

1. Check history for recent new drugs, foods, infections (most common triggers)
2. Start cetirizine 10 mg daily (or levocetirizine 5 mg)
3. If very itchy and disturbing sleep, add hydroxyzine 25 mg at bedtime
4. If wheals are large or spreading, short course of prednisolone 20-40 mg/day x 3-5 days provides rapid relief
5. If lesions persist > 6 weeks - classify as chronic urticaria and investigate for underlying cause (thyroid antibodies, ANA, CBC, LFT)
6. Avoid NSAIDs and aspirin (can trigger or worsen urticaria)

Note: If the patient develops facial/throat swelling, difficulty breathing, or dizziness, treat as anaphylaxis and refer immediately to emergency care.

Oral Regimen (preferred if no airway symptoms)

The steroid burst rapidly suppresses the allergic response. Do NOT use long-term.

Add-on for Breakthrough Itch

• Montelukast 10 mg once at night - leukotriene blocker, works synergistically with antihistamine
• Calamine lotion topically for immediate itch relief (cooling effect)
• Cold compress on wheals - reduces histamine release locally

If Still Not Controlled (48-72 hrs)

• Escalate to Chlorphenamine 4 mg q6h (sedating first-gen H1) as bridging
• Or Dexamethasone 4-8 mg IM/IV single dose if very severe

Key Advice to Patient

1. Avoid scratching - breaks skin, risks secondary infection
2. Wear loose, cotton clothing
3. Avoid heat, tight clothing, hot showers - all worsen histamine release
4. Identify and stop any new drug, food, or supplement started recently
5. Return immediately if lips/tongue/throat swell or breathing difficulty

Red Flag - Refer to Emergency If:

• Throat/tongue swelling (angioedema)
• Hoarse voice or stridor
• Difficulty breathing or swallowing
• Dizziness/drop in BP → anaphylaxis protocol with epinephrine 0.3 mg IM

What They've Done ✓

• Cetirizine 10 mg taken - good. It will start working within 1-2 hours. Peak effect at 4-6 hours.

Right Now - Non-Drug Measures (Do Immediately)

1. Cold compress / ice pack wrapped in cloth - apply directly on wheals for 10-15 mins. Cold constricts blood vessels and suppresses histamine release. Repeat every 30 mins.
2. Cold water rinse - run cool/cold water over the arm for 5-10 minutes
3. Do NOT scratch - scratching releases more histamine → more itch → more wheals (vicious cycle)
4. Remove tight clothing/sleeves - pressure on skin worsens urticaria
5. Stay in a cool room / use a fan - heat worsens itching significantly
6. Avoid hot food, spicy food, alcohol right now - all trigger histamine release

Next Cetirizine Dose

• If itching is still bad after 24 hours, take the next Cetirizine 10 mg
• Do NOT double dose at once

Get These ASAP (basic pharmacy items)

1. Prednisolone 20-40 mg (very cheap, widely available) - most effective for acute flare
2. Chlorphenamine / Pheniramine tablets - cheap, available everywhere
3. Calamine lotion - topical, immediate cooling relief

Go to Emergency NOW if any of these appear:

• 🚨 Swelling of lips, tongue, or throat
• 🚨 Difficulty breathing or swallowing
• 🚨 Dizziness or feeling faint
• 🚨 Wheals spreading rapidly over whole body