This is the disease that infected my son; Afnan last week:
Henoch-Schönlein purpura (very weird name)
In medicine (rheumatology and pediatrics) Henoch-Schönlein purpura (HSP, also known as allergic purpura) is a systemic vasculitis (inflammation of blood vessels) characterized by deposition of immune complexes containing the antibody IgA, especially in the skin and kidney. It occurs mainly in children. Typical symptoms include palpable purpura (small hemorrhages in the skin), joint pains and abdominal pain. Most cases are self-limiting and require no treatment apart from symptom control, but the disease may relapse (in 33% of cases) and cause irreversible kidney damage (in 1%).
Signs and symptoms
Purpura, arthritis and abdominal pain are known as the "classic triad" of Henoch-Schönlein purpura. Purpura occur in all cases, joint pains and arthritis in 80%, and abdominal pain in 62%. Some include gastrointestinal hemorrhage as a fourth criterion - this occurs in 33% of cases (sometimes but not necessarily due to intussusception). The purpura typically appear on the legs and buttocks, but may also be seen on the arms, face and trunk. The abdominal pain is colicky in character. The joints involved tend to be the ankles, knees, and elbows but arthritis in the hands and feet is possible; the arthritis is non-erosive and hence causes no permanent deformity. 40% have evidence of kidney involvement, mainly in the form of hematuria (blood in the urine), but only a quarter will have this in sufficient quantities to be noticeable without laboratory tests. Problems in other organs, such as the central nervous system (brain and spinal cord) and lungs may occur, but much less commonly than the skin, bowel and kidneys.
The disease tends to last about 4 weeks, and then resolves spontaneously.
Most patients do not receive therapy because of the high spontaneous recovery rate. Steroids are generally avoided. However, if they are given early in the disease episode, the duration of symptoms may be shortened, although abdominal pain does not improve significantly. Moreover, the chance of severe kidney problems is reduced.
Evidence of worsening kidney damage would normally prompt a kidney biopsy. Treatment may be indicated on the basis of the appearance of the biopsy sample; various treatments may be used, ranging from oral steroids to a combination of intravenous methylprednisolone (a potent steroid), cyclophosphamide and dipyridamole followed by prednisone. Other regimens include steroids/azathioprine, and steroids/cyclophosphamide (with or without heparin and warfarin). Intravenous immunoglobulin (IVIG) is occasionally used.
HSP occurs more often in children than in adults, and usually follows an upper respiratory tract infection. Half of affected patients are below the age of six, and 90% under ten. It occurs more often in boys than in girls (about twice as often).
The incidence of HSP in children is about 20 per 100,000 children per year; this makes it the most common vasculitis in childhood.
The disease carries the name of Eduard Heinrich Henoch (1820-1910), a German pediatrician, and his teacher Johann Lukas Schönlein (1793-1864), who described it in the 1860s. The English physician William Heberden (1710-1801) and the dermatologist Robert Willan (1757-1812) had already described the disease in 1802 and 1808, respectively, but the name Heberden-Willan disease has fallen into disuse. William Osler would be the first to see HSP as a form of allergy.