Eosinophilic granulomatosis with polyangiitis (EGPA) or allergic granulomatosis is now the preferred term for Churg-Strauss syndrome. It is an ANCA associated small-medium vessel vasculitis, characterized by airway atopy; pulmonary-renal syndrome.

EGPA share many features with PAN, so think of PAN in an asthmatic patient.

Features

• asthma
• blood eosinophilia (e.g. > 10%)
• paranasal sinusitis
• mononeuritis multiplex
• renal involvement occurs in around 20%
• pANCA positive in 60%

Leukotriene receptor antagonists may precipitate the disease.

The disease progression can be crudely divided into three phases.

1. Initially, there is a prodromal phase characterised by atopy.
2. This is followed by an eosinophilic phase of which features include pulmonary opacities, asthma and eosinophilia.
3. Finally, there is a vasculitis phase with a broad range of potential organ involvement.

Diagnosis

The American College of Rheumatology 1990 criteria for diagnosis of Churg-Strauss Syndrome lists the following criteria:

1. Asthma
2. Eosinophils greater than 10% of a differential white blood cell count
3. Presence of mononeuropathy or polyneuropathy