This article is more than 5 years old. Information may no longer be current.
An 8-year-old child with a rash and left knee pain
Click Here to Manage Email Alerts
An 8-year-old male child was seen with a rash and left knee pain. The rash started 2 days ago in the lower legs bilaterally as small red spots that progressed to raised maculopapular areas mixed with urticarial wheals. Accompanying symptoms were pain in the knee joint that started the day after appearance of the rash. Pain affected the left knee; 5 to 6 of 10 in severity, exacerbated by movement and partially relieved by nonsteroidal anti-inflammatory drugs.
He was diagnosed and treated for streptococcal pharyngitis about 1 week before onset of the rash.
On examination, the skin over the lower leg and calf region demonstrated a polymorphic rash with well-circumscribed indurated erythematous purpuric papules, blanching on pressure. The surrounding skin over the lower extremity showed areas of raised maculopapular lesions mixed with urticarial wheals. There were no other areas of skin involvement elsewhere on the body.
Left knee exam was significant for mild edema and tenderness on extension. No limitation of joint movement in other joints was noted. The remainder of the physical exam was noncontributory.
 |
|
Erythematous macules, Purpuric and
urticarial papules, of the lower extremity in an 8-year-old.
|
What is the most likely etiology?
Answer: Henoch-Schönlein purpura
The most common cause of self-limiting vasculitis in the pediatric age group is a systemic manifestation by immunoglobulin A antibodies.
The disease is characterized by a fourfold cluster of manifestation:
- Palpable purpura in patients with neither thrombocytopenia nor coagulopathy.
- Arthritis/arthralgia.
- Diffuse, colicky abdominal pain associated with vomiting.
- Renal disease seen as hematuria, proteinuria, and in some, nephritic syndrome.
Diagnosis is usually made as per the Pediatric Rheumatology Society classification, which mandates palpable purpura as an essential feature along with any one of the above-mentioned clinical presentation.
The common differentials for Henoch-Schönlein purpura are: idiopathic thrombocytopenic purpura, thrombotic thrombocytopenic purpura, disseminated intravascular coagulopathy, rheumatic fever, Rocky Mountain spotted fever, Lyme disease, meningococcal septicemia, septic emboli, toxic vasculitis and testicular torsion (due to scrotal edema in Henoch-Schönlein purpura).
Henoch-Schönlein purpura is a clinical diagnosis but can be confirmed by skin biopsy that shows a tell-tale picture of IgA-Ab and C3 deposition along medium- and small-sized blood vessel wall on immunofluorescence. The pathologic picture of Henoch-Schönlein purpura is leukocytoclastic vasculitis.
Usually, symptomatic conservative management is warranted, unless renal system involvement is not observed.
The condition carries a good prognosis, with close to 90% of cases showing spontaneous resolution of symptoms. Less than 5% of cases cause chronic symptoms.
Less than 1% of cases progress to end-stage renal failure. Symptoms may recur in children aged younger than 10 years.
Treatment is generally supportive and includes rest, NSAIDs and reassurance. Other less common treatments for more persistent and bothersome nodules include potassium iodide, colchicine and intralesional steroid injections or oral corticosteroids. Recurrence is uncommon in children. Practitioners should be aware of this common, self-limited hypersensitivity reaction in children so that patients are appropriately evaluated and treated as needed.
Pearls to remember
- Not all purpuric areas of skin have an underlying platelet defect — quantitative or qualitative.
- The natural course of the disease — triggering illness followed by appearance of rash in 1 to 2 weeks, accompanied or followed closely by accompanying signs/symptoms of the tetrad.
- Henoch-Schönlein purpura that leads to abdominal colic and vomiting may progress to intussusception.
- Labs will show raised antistreptolysin-O titers with normal complement levels.
- IgA nephropathy and Henoch-Schönlein purpura have similar pathogenesis, and close follow-up is needed in children of Henoch-Schönlein purpura with renal involvement to prevent/manage nephrotic syndrome.
Akshat Jain, MD, is a second-year pediatric resident at the New York Medical College, Metropolitan Hospital in New York City.
For more information:
- Lanzkowsky S. Pediatr Rev. 1992;13:130-137.
- Miller ML. Vasculitis syndromes. In: Kliegman RM, Behrman RE, Jenson HB, Stanton B, eds. Nelson Textbook of Pediatrics, 18th edition; Philadelphia, Pa: ElsevierSaunders; 2007:1042-1049.
- Saulsbury FT. Lancet. 2007;369:976-978.
- Weiss PF. Pediatrics. 2007;120:1079-1087.
Disclosure: Dr. Jain reports no relevant financial disclosures.