Pemphigus is a rare, chronic, life-threatening autoimmune blistering disease characterized by blisters and erosions of the skin and mucous membranes. Rituximab has been approved as a first-line treatment for moderate to severe pemphigus vulgaris. Despite of its efficacy in achieving remission, Rituximab can also lead to serious complications such as Hepatitis B reactivation.

We present a case of a 42-year-old Filipino male with severe pemphigus vulgaris on chronic immunosuppressive therapy. He had a 10-month history of multiple bullae and crusted erosions associated with pruritus and burning pain on the mouth resulting to odynophagia and dysphagia. He is a known case of chronic Hepatitis B with unrecalled vaccination status. On physical examination, Nikolsky and Asboe-Hansen signs were positive. Histopathology show intraepidermal split and row of suprabasal keratinocytes pattern. ELISA showed very high levels (>200 RU/ml) for both anti-desmoglein 1 & 3. DIF was positive for IgG & C3. Prior to Rituximab administration, Tenofovir 300 mg/tab/day was started as pre-emptive therapy. To lessen the dependence on systemic corticosteroids, two infusions of Rituximab 1g 2 weeks apart were then given. Notable improvement was seen, evidenced by absence of new bullae, reduction of affected BSA, from 19% to 5.3% and decreased PDAI (78 to 1) and ABSIS (46.5 to 2.75) four months after treatment. Maintained remission and undetectable Hepatitis B viral load 4 months following the last dose of Rituximab were noted, indicating a positive treatment response to both Rituximab and Tenofovir.

Rituximab represents a viable treatment option even for patients with chronic Hepatitis B. Pre-emptive therapy may be done prior to infusion to prevent hepatitis reactivation. Clinical evidence supports the efficacy and safety of Rituximab in this case where preventive measures are taken.