Leukocytoclastic Vasculitis

A 6-year-old girl was evaluated in the emergency department for a leg rash that had spread to the buttocks. The lesions first appeared earlier in the day and worsened hourly. The child's mother reported that her daughter was in good health until a low-grade fever, nonproductive cough, sore throat, and headache developed 5 days earlier. The youngster also complained of neck pain with movement.

The raised, purpuric, bilateral lower extremity rash erupted in crops that ranged from 0.3 cm to 2 cm in diameter. The lesions did not blanch with palpation. The patient also had exudate on her left tonsil and nuchal rigidity.

A lumbar puncture revealed no evidence of meningitis. White blood cell count was 12.9 × 10³/µL, with 72% neutrophils, 21% lymphocytes, 5% eosinophils, and 2% monocytes; hemoglobin, 12.6 g/dL; hematocrit, 36.3%; and platelet count, 294,000/µL. Coagulation studies and serum chemistry panel showed no abnormalities; no occult blood was found in the stool. Urinalysis revealed microscopic hematuria with trace protein and amorphous urate sediment.

A diagnosis of Henoch-Schnlein purpura (HSP) was made; the youngster was followed up as an outpatient.

Dr Jerzy Slomka of Ellsworth, Kan, and J. Patrick Carter, PA-C, of Norwalk, Conn, report that the incidence of HSP in the United States is estimated to be 14 per 100,000 children per year. The average age at onset ranges from 2 to 14 years; boys are affected twice as often as girls. The disease has no race predilection.

HSP is an IgA-mediated leukocytoclastic inflammatory reaction of polymorphonuclear and round cells. The cause is unknown; however, allergy and drug sensitivity play a crucial role in some patients. In 50% of cases, HSP follows an upper respiratory tract infection, with 75% of the infections caused by streptococci. The reaction also may be triggered by drugs, chemical toxins, insect bites, certain foods, and viral pathogens.

Capillaries are most frequently involved with scattered nuclear debris, edema, and swelling of collagen fibrils found adjacent to affected vessels. Arthritis of the knees and ankles and dermal symptoms are self-limited; however, involvement of the kidneys and gastrointestinal (GI) tract can lead to further complications.

The clinical diagnosis is based on the characteristic palpable, purpuric rash, with or without renal or GI involvement. A skin biopsy will reveal leukocytoclastic vasculitis. When GI symptoms are present, the diagnosis may be facilitated by ultrasonography, which can detect intraluminal hematomas, duodenal wall thickening, and accompanying luminal enlargement.

Treatment is aimed at symptom relief. Offending agents must be removed or avoided. Anti-inflammatory agents can be used for arthritis pain. Corticosteroids do not alter the progression of the cutaneous lesions; however, they have been shown to be helpful in treating IgA nephropathy.

Plasmapheresis has been reported as effective in the treatment of severe disease; azathioprine, cyclophosphamide, and factor XIII also have been tried. Renal involvement signals a poorer prognosis, but the majority of patients with HSP recover without lasting sequelae.

This youngster's rash cleared within 4 weeks; the hematuria and proteinuria resolved as well. However, the patient continues to note intermittent arthralgia of the left knee.