If urticaria occurs before starting Ilumya (tildrakizumab), how should it be managed before initiating therapy?

Management of Pre-Existing Urticaria Before Initiating Ilumya

If urticaria is present before starting Ilumya, you must first determine whether this represents a serious hypersensitivity reaction or chronic spontaneous urticaria, as Ilumya is contraindicated in patients with previous serious hypersensitivity reactions to tildrakizumab, and cases of urticaria have occurred in clinical trials as hypersensitivity reactions. 1

Critical Initial Assessment

Determine the nature of the urticaria:

• If the urticaria is acute and potentially drug-related or allergic: Do not initiate Ilumya until the reaction has completely resolved and the trigger has been identified and eliminated. The FDA label explicitly warns that urticaria can occur as a hypersensitivity reaction to Ilumya, and if a serious hypersensitivity reaction occurs, the drug must be discontinued immediately 1.

• If the urticaria is chronic spontaneous urticaria (CSU): This is a separate mast cell-driven condition that may coexist with psoriasis and requires its own management pathway before considering Ilumya initiation.

Management Algorithm for Chronic Spontaneous Urticaria

If the urticaria represents CSU (wheals recurring for >6 weeks), follow this stepwise approach before initiating Ilumya:

Step 1: First-Line Treatment (2-4 weeks)

• Start standard-dose second-generation H1-antihistamine (non-sedating)
• If symptoms are intolerable or inadequate control after 2-4 weeks, proceed to Step 2 2

Step 2: Updose Antihistamines

• Increase second-generation H1-antihistamine up to 4-fold the standard dose
• Continue for 2-4 weeks
• If inadequate control persists, proceed to Step 3 2

Step 3: Add Omalizumab

• Add omalizumab 300 mg every 4 weeks to the antihistamine regimen
• Allow up to 6 months for response
• If inadequate response, consider updosing omalizumab (up to 600 mg every 2 weeks) 2

Step 4: Consider Cyclosporine

• If omalizumab fails, add cyclosporine (up to 5 mg/kg body weight) to antihistamines
• Monitor blood pressure and renal function (BUN, creatinine) every 6 weeks 2

Key Considerations Before Ilumya Initiation

Do not start Ilumya if:

• Active urticaria is uncontrolled and potentially represents an allergic/hypersensitivity state
• The patient has any clinically important active infection (Ilumya increases infection risk) 1

Safe to proceed with Ilumya when:

• CSU is adequately controlled on the above regimen (antihistamines ± omalizumab ± cyclosporine)
• The urticaria has completely resolved if it was acute/allergic in nature
• At least 2-4 weeks have passed since urticaria resolution to ensure stability

Important Caveats

Monitor closely after Ilumya initiation: Even with controlled CSU, remain vigilant for new-onset urticaria or angioedema as these can represent hypersensitivity reactions to Ilumya itself. If serious hypersensitivity develops, discontinue Ilumya immediately and initiate appropriate therapy 1.

Concurrent management: Patients with both psoriasis and CSU can continue their urticaria treatment regimen (antihistamines, omalizumab, or cyclosporine) while receiving Ilumya for psoriasis, as these address different pathophysiologic mechanisms.

Diagnostic workup for CSU: Before labeling as CSU, obtain basic tests including differential blood count, C-reactive protein/ESR, total IgE, and IgG-anti-thyroid peroxidase levels to assess for autoimmune or autoallergic mechanisms 2.