What is the management of hives (urticaria) in post-transplant patients?

Management of Hives (Urticaria) in Post-Transplant Patients

Treat post-transplant urticaria with standard antihistamine therapy while simultaneously investigating for donor-derived allergy transfer, particularly in liver, lung, and pancreas recipients, as this represents a potentially life-threatening condition requiring strict allergen avoidance and emergency epinephrine prescription. 1

Immediate Assessment and Treatment

Acute Urticaria Management

• Administer second-generation antihistamines as first-line therapy for symptomatic relief of hives, avoiding first-generation antihistamines when possible due to sedation and other side effects 2
• Stop any recently introduced medications immediately if drug reaction is suspected, though diagnosis may be complicated by concurrent high-dose corticosteroid therapy that can mask allergic responses 3
• Monitor closely for progression to anaphylaxis, including respiratory symptoms (dyspnea, tachypnea), gastrointestinal symptoms (vomiting, abdominal pain), or cardiovascular compromise 1, 2

Critical Pitfall to Avoid

Do not dismiss urticaria as a simple drug reaction without investigating donor allergy history, especially in liver, lung, and pancreas recipients where IgE transfer occurs most frequently and can manifest as severe anaphylaxis 1

Investigation for Donor-Derived Allergy Transfer

High-Risk Recipients Requiring Urgent Workup

• Liver, lung, and pancreas transplant recipients are at highest risk for clinically significant allergy transfer and should undergo immediate allergological evaluation if urticaria develops 1
• Kidney and heart recipients have lower risk but should still be evaluated if symptoms are severe or recurrent 1

Diagnostic Testing Protocol

• Perform skin prick testing (SPT) and specific IgE testing as early as 7 days post-transplant - immunosuppression with tacrolimus, mycophenolate mofetil, and corticosteroids does not prevent accurate diagnosis 1
• Discontinue antihistamines 7 days prior to skin prick testing to avoid false-negative results, though this should be balanced against symptom control 1, 4
• Check recipient's baseline atopic status using qualitative serological screening (e.g., Phadiatop) and total IgE measurement, as atopic patients appear at higher risk for allergy transfer 1
• Test for recombinant allergens (particularly food allergens like Ara h1, h2, h3, h6 for peanuts) as these predict clinically relevant allergy transfer 1

Donor History Investigation

• Obtain detailed donor allergy history from donor family, specifically asking about severe allergic reactions to foods (especially peanuts, tree nuts, fish, milk, eggs), hymenoptera venom, and drugs 1
• Review donor cause of death - if anaphylaxis was involved, perform specific IgE testing on stored donor serum as first-line investigation 1

Management Based on Allergy Transfer Risk Stratification

High-Risk Recipients (Confirmed Donor Allergy History)

• Prescribe self-injectable epinephrine device immediately and provide emergency action plan 1
• Institute strict avoidance of identified allergens - this is non-negotiable as transferred allergies can cause grade III-IV anaphylaxis 1
• Perform detailed allergy workup with serial SPT and specific IgE monitoring over time 1
• Do not perform oral food challenge until SPT and IgE have completely normalized or remain at very low levels with negative recombinant allergen testing 1

Intermediate-Risk Recipients (Urticaria Without Known Donor History)

• Conduct donor serological analysis retrospectively if samples available 1
• Perform recipient skin and serological testing to establish new sensitizations 1
• Provide antihistamine therapy for symptom control while investigation proceeds 2

Monitoring Protocol for Transferred Allergies

• Repeat SPT and IgE testing serially - transferred IgE sensitization is often transient, typically resolving within weeks to months 1
• Continue strict allergen avoidance until testing normalizes, which may take 3-24 weeks for food allergies or persist up to 7 years in rare cases 1
• Consider oral challenge only after documented negative testing to prove tolerance 1

Special Considerations in Transplant Context

Impact of Immunosuppression

• Standard immunosuppressive regimens (basiliximab induction, tacrolimus, mycophenolate mofetil, corticosteroids) do not prevent detection of IgE sensitization or suppress skin test reactivity significantly 1
• Avoid excessive immunosuppression if urticaria meets diagnostic criteria for atopic dermatitis rather than rejection 5

Differential Diagnosis Challenges

• Consider graft-versus-host disease in liver transplant recipients, though this is rare 6
• Evaluate for opportunistic infections (bacterial, viral, fungal) which commonly cause cutaneous manifestations in immunosuppressed patients 7, 6
• Drug reactions are common but may be difficult to diagnose in patients on high-dose corticosteroids 3
• IgE-mediated food allergies develop in 12.2% of liver transplant patients and can present as urticaria, angioedema, or life-threatening anaphylaxis 6

Documentation and Follow-Up

• Document all new allergic reactions in transplant records to inform future medical care 8
• Coordinate care between transplant team and allergist for comprehensive management 1
• Educate patients and families about signs of anaphylaxis and proper epinephrine use 1