How should I treat pruritic hives in a patient with psoriasis who is receiving Ilumya (tildrakizumab)?

Treatment of Pruritic Hives in Patients on Ilumya (Tildrakizumab)

Start with a non-sedating H1-antihistamine at standard dosing (such as cetirizine, fexofenadine, or loratadine once daily), and if inadequate response within 1-2 weeks, increase the dose up to 4 times the standard dose before considering other interventions. 1

Initial Assessment and Drug Relationship

First, determine if the urticaria represents a hypersensitivity reaction to Ilumya itself. The FDA label explicitly warns that cases of angioedema and urticaria have occurred in Ilumya-treated patients in clinical trials 2. If this is a serious hypersensitivity reaction (angioedema, severe urticaria, systemic symptoms), discontinue Ilumya immediately and initiate appropriate therapy 2.

However, if the hives are mild to moderate without angioedema or systemic features, they may represent:

• A mild hypersensitivity that can be managed symptomatically while continuing psoriasis treatment
• Coincidental chronic spontaneous urticaria unrelated to Ilumya
• A transient reaction that may resolve with symptomatic treatment

Stepwise Treatment Algorithm

First-Line: H1-Antihistamines

Offer the patient a choice of at least two non-sedating H1-antihistamines because individual responses vary 1. Options include:

• Cetirizine 10 mg once daily (fastest time to maximum concentration, though may cause some sedation)
• Fexofenadine 180 mg once daily
• Loratadine 10 mg once daily
• Desloratadine 5 mg once daily (longest elimination half-life at 27 hours)
• Levocetirizine 5 mg once daily

Dose Escalation if Needed

If symptoms persist after 1-2 weeks at standard dosing, increase the antihistamine dose up to 4 times the manufacturer's licensed recommendation 1. This is common practice when potential benefits outweigh risks. For example:

• Cetirizine up to 40 mg daily
• Fexofenadine up to 720 mg daily
• Loratadine up to 40 mg daily

Adjunctive Symptomatic Measures

• Apply cooling antipruritic lotions such as calamine or 1% menthol in aqueous cream for immediate relief 1
• Avoid aggravating factors: overheating, stress, alcohol, aspirin, NSAIDs, and codeine 1
• NSAIDs should be completely avoided if there is any history of aspirin sensitivity with urticaria 1

When to Consider Discontinuing Ilumya

Discontinue Ilumya if:

• Serious hypersensitivity reaction occurs (angioedema, anaphylaxis, severe widespread urticaria) 2
• Urticaria persists or worsens despite maximal antihistamine therapy
• Quality of life impact from urticaria outweighs psoriasis control benefits

Alternative Considerations if Antihistamines Fail

If high-dose antihistamines are insufficient and you determine the urticaria is not directly related to Ilumya (allowing continuation):

• Short course of systemic corticosteroids (0.5-1 mg/kg/day prednisone for 5-7 days) for acute severe flares
• Ciclosporin 4 mg/kg/day has the strongest evidence for antihistamine-resistant chronic urticaria, effective in about two-thirds of patients 1
• Consider switching to an alternative IL-23 inhibitor (guselkumab or risankizumab) if you suspect drug-specific hypersensitivity

Critical Pitfalls to Avoid

• Do not assume all urticaria during biologic therapy is drug-related—chronic spontaneous urticaria is common in the general population
• Do not use sedating antihistamines as first-line unless non-sedating options have failed
• Do not delay dose escalation of antihistamines—waiting months at standard dosing wastes time
• Do not use topical corticosteroids routinely for urticaria—they provide minimal benefit 1
• Do not confuse urticaria with other cutaneous reactions that might indicate more serious drug reactions requiring immediate discontinuation

Monitoring Strategy

• Reassess at 1-2 weeks after initiating antihistamine therapy
• If improving, continue current regimen and monitor
• If stable or worsening, escalate antihistamine dose
• Document temporal relationship between Ilumya injections and urticaria episodes to help determine causality
• Monitor for any signs of serious hypersensitivity (respiratory symptoms, hypotension, severe angioedema)

The prognosis for urticaria resolution is generally excellent, though some cases may persist 1. The key is balancing effective psoriasis control with management of this adverse effect, recognizing that mild urticaria can often be controlled symptomatically without sacrificing the benefits of Ilumya therapy.