EGPA diagnosis

Q: Which of the following is NOT  a part of the diagnostic criteria for eosinophilic granulomatosis with polyangiitis (EGPA) (Churg-Strauss) per the American College of Rheumatology (ACR)? (select one)

A) Asthma 

B) Greater than 10 percent eosinophils on the differential leukocyte count

C) Migratory or transient pulmonary opacities detected radiographically

D) Paranasal sinus abnormality

E) Tender subcutaneous nodules on the extensor surfaces of the arm and legs

Answer: E

There are two well-known criteria for EGPA. The ACR and the Lanham criteria. Said that experts believe that in light of new advances and literature, there is a need to propose, modify or update new criteria.

The Lanham criteria was proposed in 1984, has three components and all three need to be met to establish the diagnosis of EGPA

• asthma
• peak peripheral blood eosinophilia over 1500 cells/microL, and 
• systemic vasculitis involving two or more extra-pulmonary organs

The ACR criteria was first proposed in 1990 and has six components. The presence of four or more of these criteria had a sensitivity of 85 percent and a specificity of 99.7 percent

• Asthma (a history of wheezing or the finding of diffuse high-pitched wheezes on expiration)
• Greater than 10 percent eosinophils on the differential leukocyte count
• Mononeuropathy (including multiplex) or polyneuropathy
• Migratory or transient pulmonary opacities detected radiographically
• Paranasal sinus abnormality
• Biopsy containing a blood vessel showing the accumulation of eosinophils in extravascular areas 

However, the tender subcutaneous nodules on the extensor surfaces of the arm, particularly the elbows, hands, and legs (choice E) are frequently found in these patients but are not a part of the criteria.

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References:

1. Lanham JG, Elkon KB, Pusey CD, Hughes GR. Systemic vasculitis with asthma and eosinophilia: a clinical approach to the Churg-Strauss syndrome. Medicine (Baltimore) 1984; 63:65.

2. Masi AT, Hunder GG, Lie JT, et al. The American College of Rheumatology 1990 criteria for the classification of Churg-Strauss syndrome (allergic granulomatosis and angiitis). Arthritis Rheum 1990; 33:1094.

3. Cottin V, Bel E, Bottero P, et al. Revisiting the systemic vasculitis in eosinophilic granulomatosis with polyangiitis (Churg-Strauss): A study of 157 patients by the Groupe d'Etudes et de Recherche sur les Maladies Orphelines Pulmonaires and the European Respiratory Society Taskforce on eosinophilic granulomatosis with polyangiitis (Churg-Strauss). Autoimmun Rev 2017; 16:1.