Eosinophilic granulomatosis with polyangiitis (Churg-Strauss)

The eosinophilic granulomatosis with polyangiitis or Churg-Strauss syndrome (CSS) is an allergic granulomatous vasculitis characterized by necrotizing inflammation of small- to medium-caliber blood vessels, marked by the presence of eosinophilic infiltrates and giant cell granulomas peri- and extravascularly.

Clinical

The clinical presentation is similar to that of polyarteritis nodosa (PAN): frequent polyneuropathies and gastrointestinal involvement, skin lesions more common than in PAN [fairly typical skin nodules – red/purplish, sometimes painful, ranging from 2-20 mm in diameter, ++ on the extensor surfaces of the elbows, fingers, and scalp – present in 1/3 of patients],… except for:

• 100% are asthmatic in the stable phase, often with a history of allergic conditions.

Evolution occurs in 3 phases:

• Late onset of asthma, often in individuals with a history of allergic skin or respiratory conditions (allergic rhinitis, nasal polyps, hay fever, drug sensitivity) without a family history of atopy.
• Blood and tissue eosinophilia, a phase that can last several years.
• Within an average of 9 years: onset of systemic vasculitis over a few weeks with quickly evident clinical severity.

Diagnosis

The diagnosis is primarily clinical, with biology providing orientation and biopsy confirming it.

Clinical suspicion

The combination of febrile asthma, with or without pulmonary infiltrates on radiography, significant deterioration of general condition, and eosinophilia should raise the suspicion of the diagnosis. One should look for systemic signs of the disease (arthritis, myalgias, purpura, abdominal pain,…). If polyneuropathy and pANCA are significantly present, the diagnosis can already be asserted.

Biology

• Eosinophilia (> 1000/mm³) and increased IgE levels.
• pANCA (anti-MPO type) present in 60%.
• Similar to PAN results.

Angiography

Less productive than in PAN.

Biopsy

Of moderate yield; its negativity is not sufficient to exclude the diagnosis. Biopsy sites: skin, nerve, muscle.

Therapeutic management - Treatments

Similar to the treatment of PAN (variable combination of prednisone and immunosuppressants).

Bibliography

EMC, traité de médecine AKOS, Elsevier, 2018

Jameson JL et al., Harrison's Principles of Internal Medicine, 20th edition, McGraw Hill Higher Education, 2018