Which systemic corticosteroid and dosing regimen is recommended for a child with acute urticaria refractory to second‑generation H1 antihistamines?

Oral Prednisolone for Severe Pediatric Hives

For children with acute urticaria refractory to second-generation H1 antihistamines, use oral prednisolone (or equivalent corticosteroid) as a short 3-day course, restricting use only to severe cases or those with angioedema affecting the mouth. 1

When to Use Corticosteroids in Pediatric Urticaria

Corticosteroids should be reserved for specific severe presentations only:

• Use oral corticosteroids exclusively for severe acute urticaria or angioedema involving the mouth 1, 2
• Do not use corticosteroids as routine add-on therapy to antihistamines—recent evidence shows that adding prednisone to cetirizine or levocetirizine does not improve symptoms compared to antihistamine alone in 2 out of 3 randomized controlled trials 3
• The evidence for corticosteroid benefit in acute urticaria is questionable, making their routine use unjustified 1

Specific Corticosteroid Dosing

Prednisolone is the recommended oral corticosteroid:

• Use a 3-day course in children (adapted from the adult recommendation) 1, 2
• While specific pediatric dosing is not detailed in the guidelines, standard practice uses weight-based dosing (typically 1-2 mg/kg/day, maximum 40-60 mg/day)
• Never continue beyond 3-10 days due to cumulative toxicity that is dose and time dependent 1, 2, 4

Critical Treatment Algorithm Before Considering Steroids

Before resorting to corticosteroids, ensure you have exhausted antihistamine optimization:

1. Start with standard-dose second-generation H1 antihistamines (cetirizine, loratadine, fexofenadine) 1
2. If inadequate response after 2-4 weeks, increase up to 4 times the standard dose (though this exceeds manufacturer recommendations) 1, 2
3. Trial a different second-generation antihistamine if one fails, as individual responses vary significantly 2
4. Consider adding an H2-antihistamine for additional histamine receptor blockade 2
5. Add a leukotriene receptor antagonist as combination therapy in resistant cases 2

Age-Specific Antihistamine Dosing for Context

For toddlers (2-5 years):

• Cetirizine: 2.5 mg once or twice daily 5
• Levocetirizine: 1.25 mg daily 5
• Desloratadine: 1.25 mg daily 5

For children 2-11 years:

• Fexofenadine: 30 mg twice daily 5

Common Pitfalls to Avoid

• Do not use corticosteroids for longer than 3-10 days—the cumulative toxicity outweighs any potential benefit 1, 4
• Do not use corticosteroids as first-line therapy or routine add-on to antihistamines 3
• Avoid first-generation antihistamines as primary therapy due to sedation impairing school performance, though they may be added at night for sleep in resistant cases 1
• Do not conclude treatment failure without first increasing antihistamine doses up to 4-fold 5
• Watch for peptic ulceration with high-dose, short-term corticosteroid therapy, though uncommon 6

Emergency Situations Requiring Different Management

• For anaphylaxis or severe laryngeal angioedema, intramuscular epinephrine is life-saving and first-line 1, 5
• Weight-based epinephrine dosing: 150 µg for children 15-30 kg, 300 µg for those over 30 kg 1