P05 Adalimumab treatment of refractory Blau syndrome: a case report and literature review

Extract

Background: Blau syndrome is a monogenic autoinflammatory condition of early childhood resulting from mutations in the gene for pattern recognition receptor NOD2 (chromosomal region 16q12.1). It presents with a classic phenotypic triad of granulomatous polyarthritis, uveitis and dermatitis. Due to the rarity of the condition (incidence <1 per 1.5million) there is a paucity of evidence regarding management, especially for cutaneous manifestations.

Methods: We describe a case and literature review of refractory rash associated with Blau syndrome.

Case report

An 11 week old female was referred to dermatology with persistent and widespread papular rash present since two weeks of age and was diagnosed with papular urticaria. The rash was flexural but not puritic and did not respond to modrasone cream. Total IgE level (4) excluded atopic eczema. Punch biopsy revealed granulomatous inflammation prompting the possibility of sarcoidosis. Further investigation excluded infectious causes. Serum Angiotensin-Converting Enzyme was slightly high (72) and chest-x-ray was normal. One month of oral prednisone (20mg decreasing by 5mg/week) provided partial improvement. At paediatric rheumatology assessment the 21 month old's rash was noted to be consistent with Blau syndrome. There was no joint or eye involvement. A novel NOD2 mutation c.1808A>G, p.(His603Arg) was confirmed. Methotrexate commenced for steroid sparing which only briefly resolved the rash and further dose increments proved futile. Asymptomatic tenosynovitis (wrists and ankles) without arthritis developed aged 27 months on methotrexate at 15mg/m². Hydroxychloroquine was added but later stopped due to lack of efficacy. Slit lamp examination was first possible aged three years and revealed mild band keratopathy (right eye) raising the possibility of previous uveitis. Rash flared following routine vaccination. Acute uveitis occurred two months later and subsequently active polyarticular arthritis developed (involving both wrists). Adalimumab 20mg every two weeks was commenced (aged three years seven months). The previously refractory rash improved rapidly, disappearing by the four week follow up. Arthritis and uveitis remain in remission after three months.