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Wang et al report an interesting case of systemic pyoderma gangrenosum (PG) with associated lung injury.1 They recognise the importance of excluding Wegener's granulomatosis (WG) in patients with respiratory symptoms and cutaneous ulceration, but in their case seem only to have done this on clinical and histopathological grounds. A more complete assessment should include testing for cANCA and anti-proteinase 3 (PR3).2
We are currently treating a 54 year old ex-smoker who presented for investigation of haemoptysis and who subsequently developed episcleritis and skin lesions resembling PG. Initial investigations were Hb 11.3 g/dl, WBC 9.4 × 109/l, platelets 401 × 109/l, ESR 86 mm/h, and CRP 181 mg/l. Renal function was normal. The chest radiograph showed alveolar shadowing in the left lower zone and an HRCT scan confirmed pulmonary infiltrates. Fibreoptic bronchoscopy and transbronchial biopsy specimens were normal. Skin biopsy specimens showed epithelial cell necrosis and acute inflammatory changes with no evidence of vasculitis or granulomas, consistent with PG. The ANCA assay was positive with a cytoplasmic distribution and was directed against the proteinase 3 epitope. Despite the absence of histological evidence, the clinical features and positive ANCA supported a diagnosis of WG. One month into treatment with pulsed intravenous methylprednisolone and cyclophosphamide the patient is clinically better with resolution of haemoptysis, healing of the pyoderma-like lesions, and a fall in the CRP to 21 mg/l.
Patients with WG frequently present with non-specific signs and symptoms and a high index of suspicion is important.3 This case highlights the importance of testing for ANCA in patients with PG and respiratory tract symptoms as the treatment of WG requires prolonged immunosuppression for at least a year. Whilst PG itself may be associated with pANCA,2 the presence of cANCA directed against PR3 is highly suggestive of WG. The histological features of WG are often patchy in distribution and the absence of the characteristic findings of vasculitis, granulomas, and necrosis does not exclude the diagnosis.3
author's reply I would like to thank Dr Perkins and colleagues for their interest in our article and for their suggestions. The ANCA assay was only introduced in our hospital in 1997 so we could not use this method to distinguish between WG and PG before that time. The diagnosis of WG in our hospital depends mainly on histopathological examination. In September 1999 the patient came for re-examination. All drugs had been stopped for more than four months, she had no symptoms, and all investigations (including chest radiograph, ESR, and CRP) were normal.
Hoffman et al reported the treatment outcome of 158 patients with WG.1-1 One hundred and thirty three patients received standard treatment of daily low dose cyclophosphamide (2 mg/kg/day) plus prednisone (1 mg/kg/day). This protocol produced marked improvement or partial remission in 91% of recipients; 75% experienced complete remission with a median time of 12 months. Less than 10% of patients so treated experienced remission as late as six years after beginning the protocol. However, 10 cases received corticosteroid only. In this group only two of six cases with limited WG (without renal injury) achieved sustained remission. The authors concluded that the course of WG had been dramatically improved by daily treatment with cyclophosphamide and a corticosteroid; other treatment regimens had not achieved such high rates of remission and successful maintenance.
Compared with Hoffman's standard protocol, the dosage of cyclophosphamide and the duration of treatment in our patient were lower and shorter, respectively. We feel it is unlikely that the clinical picture would have improved so significantly within 10 days if the diagnosis was WG. Of course, the best way is to perform an ANCA test and we intend to do so.