CPC03 Triad of generalized rash, peripheral eosinophilia and coexisting obstructive airway disease

Abstract

Abstract An 87-year-old woman was referred to the acute dermatology service with a 1-week history of a generalized painful rash. She was under the care of the medical team for treatment of pneumonia with symptoms of a cough, fevers and shortness of breath. Her past medical history included adult-onset asthma, hyponatraemia and hypertension. She had never smoked. On examination, she had erythematous smooth papules and plaques on her limbs and torso with palmoplantar involvement, alongside purple macules and patches where older lesions were present. There was no lymphadenopathy and no mucosal involvement. She had an oxygen requirement of 2 L per minute via nasal cannula. Initial blood tests showed eosinophils of 2.8 × 109 cells L−1 and a C-reactive protein (CRP) of 77 mg L−1. A chest radiograph showed bilateral ill-defined shadowing. Two skin punch biopsies were performed for histology and immunofluorescence. Vasculitis screen identified positive antinuclear antibodies (anti-Ro) and reduced complement C4 with negative antineutrophil cytoplasmic antibody (ANCA). The patient remained unwell with increasing CRP and peripheral eosinophilia (up to 9.2 × 109 cells L−1) with rash progressing to exhibit a reticular pattern. Alongside bilateral patchy ground glass opacification on chest computed tomography, a clinical diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA) was made. Differential diagnoses included viral exanthem, erythema multiforme and urticarial vasculitis. Screening for cardiac, renal and sinus involvement was undertaken. The patient improved clinically following the initiation of systemic steroids and the peripheral eosinophilia returned to baseline. Skin histology reinforced the clinical diagnosis of EGPA, demonstrating a dermal and perivascular eosinophilic infiltrate with focal extension into vessel walls. EGPA is a rare small- to medium-sized vessel vasculitis with an annual incidence of 0.9–2.4 per million and a median age at diagnosis of 49–59 years. The clinicopathological hallmarks, as in this case, are asthma with peripheral eosinophilia and pulmonary eosinophilic infiltrates. Median time from onset of asthma to presentation with EGPA is 5–9 years. EGPA remains a clinical diagnosis, reinforced by serological and histological findings, although ANCA is reported to be negative in 60–70% of cases. Systemic steroids are the first-line therapy, with a role for second-line immunosuppressants such as methotrexate and rituximab. The key learning points from this case are to keep an open mind in considering a systemic cause for cutaneous manifestations, especially when the patient does not fulfil the usual demographic picture.