What is the recommended approach for treating a patient with leukocytoclastic vasculitis and a history of hepatitis B (HBV) infection prior to initiating steroid therapy, considering the risk of HBV reactivation?

Management of Hepatitis B Prior to Steroid Therapy in Leukocytoclastic Vasculitis

All patients with leukocytoclastic vasculitis requiring steroid therapy must be screened for hepatitis B before initiating treatment, and HBsAg-positive patients require antiviral prophylaxis started prior to steroids to prevent potentially fatal HBV reactivation. 1, 2

Mandatory Pre-Treatment Screening

Screen all patients with at minimum HBsAg and anti-HBc testing before starting any steroid therapy. 1, 2 A comprehensive panel including HBsAg, anti-HBc, and anti-HBs provides complete risk stratification by identifying active infection, past exposure, and immunity status. 2

Risk Stratification Based on HBV Status and Steroid Regimen

High-Risk Scenarios Requiring Antiviral Prophylaxis

HBsAg-positive patients receiving moderate-dose (10-20 mg prednisone) or high-dose (>20 mg prednisone) steroids for ≥4 weeks face a 10% or higher reactivation risk and require mandatory antiviral prophylaxis. 1 This represents a high-risk category where prophylaxis must be initiated before starting steroids. 2, 3

Moderate-Risk Scenarios

HBsAg-positive patients receiving low-dose steroids (<10 mg prednisone daily) for ≥4 weeks have moderate risk (1-10% reactivation rate) and should receive prophylaxis. 1 HBsAg-negative/anti-HBc-positive patients on moderate-to-high dose steroids for ≥4 weeks also fall into moderate risk and warrant close monitoring with consideration for prophylaxis. 1

Low-Risk Scenarios

Short courses (<1 week) of any steroid dose in either HBsAg-positive or HBsAg-negative/anti-HBc-positive patients carry <1% reactivation risk and can be managed with monitoring alone. 1, 4 However, this assumes no additional immunosuppressive medications are being used concurrently. 4

Antiviral Prophylaxis Protocol

First-Line Agents

Use entecavir (0.5-1 mg daily) or tenofovir disoproxil fumarate (300 mg daily) as first-line prophylaxis due to their high barrier to resistance. 3 These are the only recommended first-line agents for HBV prophylaxis. 3

Important caveat: One case report documents tenofovir-induced leukocytoclastic vasculitis, which resolved after switching to entecavir. 5 While extremely rare, if new vasculitic lesions develop after starting tenofovir, consider switching to entecavir.

Timing and Duration

Start antiviral prophylaxis before initiating steroid therapy. 2, 3 Continue prophylaxis throughout the entire duration of immunosuppression and for at least 12 months after discontinuation of steroids. 2 This extended duration is critical as reactivation can occur months after stopping immunosuppression. 2

Monitoring Strategy

For Patients on Prophylaxis (HBsAg-positive)

• Monitor HBV DNA every 3 months until undetectable, then every 6 months 3
• Check ALT/AST every 3-6 months 3
• Monitor renal function regularly if using tenofovir due to nephrotoxicity risk 3

For Patients Being Monitored Without Prophylaxis (HBsAg-negative/anti-HBc-positive at moderate risk)

Monitor ALT, HBsAg, and HBV DNA every 3-6 months during therapy. 1, 2 This allows early detection of reverse seroconversion (reappearance of HBsAg) or viral reactivation. 1

Critical Pitfalls to Avoid

Never start steroids without HBV screening in patients requiring moderate-to-high dose or prolonged therapy. 2 Fatal cases of HBV reactivation have been reported even with very low-dose steroids (2.5 mg/day prednisone) in inactive carriers. 6 This underscores that any chronic steroid use carries risk.

Do not discontinue antiviral prophylaxis when stopping steroids. 2 Continue for at least 12 months post-immunosuppression, as late reactivation is well-documented. 2

Recognize that risk estimates are based on single-agent exposure. 1, 4 If combining steroids with other immunosuppressive agents (such as rituximab for severe vasculitis), the reactivation risk increases substantially and may shift patients from low to high-risk categories. 1

Avoid lamivudine as prophylaxis despite older case reports showing efficacy in HBV-associated vasculitis. 7 Resistance rates reach 70% after 5 years, making it unsuitable for prophylaxis. 3

Special Consideration for HBV-Associated Vasculitis

Some cases of leukocytoclastic vasculitis are directly caused by HBV immune complex deposition. 8, 9 In these cases, treating the underlying HBV infection with antivirals may improve the vasculitis itself. 8, 7 However, steroids remain necessary for acute vasculitis control, making the prophylaxis strategy even more critical. 8