A 12-year-old girl presented in early October with a one-week history of progressive and painful bullous rash of the distal lower extremities (Fig. 1a), abdominal pain, nonproductive cough, and pleuritic chest pain. She denied fevers, mucosal lesions, hematemesis, arthralgia, hematuria, melena, or hematochezia. Her medical history was notable for an identical rash that had been diagnosed as HSP four years prior, accompanied by significant abdominal pain, hematuria, and proteinuria; there was no pulmonary involvement noted at that time. She had been treated with a high-dose oral prednisone taper but did not show improvement until several weeks following completion of that treatment course. She was subsequently symptom-free in the interim. She traveled to the Outer Banks of North Carolina in the months preceding her presentation.
On physical exam, the rash on her feet and ankles was bullous and in various stages of healing, with exquisite tenderness to palpation and positive Nikolsky's sign. She had clustered vesicles with erythematous base on the bilateral extensor surfaces of her elbows as well as scattered non-blanching pinpoint erythematous macules at the inferior aspect of her bilateral buttocks. Cardiopulmonary exam was unremarkable except for an intermittent, dry cough. Her chest pain was not reproducible with palpation.
Basic labs were remarkable for elevations in inflammatory markers and a mildly impaired prothrombin time. Complete blood count and comprehensive metabolic panel were otherwise normal. Urinalysis revealed microscopic hematuria and mildly elevated protein-to-creatinine ratio. Chest X-ray was concerning for pulmonary infiltrates. Computed tomography (CT) of the chest revealed multiple peripheral pulmonary nodules most consistent with a possible fungal infection versus hemorrhagic vasculitic process (Fig. 2). Abdominal ultrasounds throughout the admission were negative for intussusception, a known complication of HSP resulting from submucosal hematoma or edema.
The differential for a pediatric patient presenting with bullous rash, abdominal pain, and pulmonary symptoms includes a broad selection of rheumatologic and infectious etiologies. Possible rheumatologic causes on the differential include pauci-immune vasculitides, Goodpastures syndrome, and systemic lupus erythematous. The appearance of the rash also raised the possibility of dermatitis herpetiformis and linear IgA bullous dermatosis. Possible infectious causes include streptococcus infection, tuberculosis, and fungal infections. A lack of convincing exposure history and low suspicion for immunocompromised state made fungal infections less likely, though the planned course of corticosteroids necessitated a fungal rule out.
Further workup revealed the following:
The results of our investigation supported the diagnosis of recurrent bullous HSP with pulmonary nodules as a new associated element of her disease flare. The mainstay of symptomatic pain management was scheduled gabapentin, rapidly up-titrated to a 700 mg total daily dose by hospital day 4 with significant improvements of the neuropathic pain in her bilateral feet and ankles. Both the pleuritic chest pain and abdominal pain persisted and were managed with as-needed oral or intravenous analgesia that provided minor benefit.
On day 6 of hospitalization, after blood cultures and a pulmonary nodule biopsy were confirmed negative for infection, intravenous methlyprednisolone (10 mg/kg daily for three days) was initiated. Her abdominal pain resolved by the following day, and the pleuritic chest pain resolved shortly thereafter. Chest X-rays following her corticosteroid burst showed interval improvement in the previously noted opacities. The patient was discharged on a two-month taper of prednisone starting at 1 mg/kg daily.
Pulmonary function test (PFT) after completing the corticosteroid course showed normal spirometry and lung volumes, with mildly reduced lung diffusion; there was no baseline PFT for comparison. Surveillance for renal manifestations continued in the outpatient setting with no signs of renal complications in the six months after discharge. Outpatient urine studies showed stable protein-to-creatinine ratio of around 300 mg/g. The patient had two episodes of arthralgias in her knees and ankles while she was still on her corticosteroid taper. Her lower extremity rashes continue to heal without additional flares, albeit slowly and with scarring (Fig. 1b). ESR and CRP both normalized on recheck five weeks after discharge, with an ESR of 5 mm/hr and CRP down to 0.02 mg/dL. Pain was well-managed with home gabapentin, and her mother noted a significant improvement in pain management compared with treatment with acetaminophen alone during initial flare four years ago.