, David G. I. Scott2 and Chetan Mukhtyar2
Department of Rheumatology, Ipswich Hospital NHS Trust, Ipswich, UK
Department of Rheumatology, Norfolk and Norwich University Hospital, Norwich, UK
Schönlein and Henoch independently described a syndrome in children comprising joint pains, purpuric cutaneous lesions, abdominal colic, and malaena. Schönlein’s description preceded the one by Henoch by about 40 years, and therefore, it is historically more accurate to term the syndrome Schönlein–Henoch purpura. William Heberden wrote about a child with arthralgia, edema, abdominal pain, vomiting, malaena, and purpura over the legs in 1801, 36 years prior to Schönlein. The eponym Henoch-Schönlein Purpura was abandoned in 2012, in favour of ‘IgA vasculitis’.
12.2 Definition and Classification
The Chapel Hill Consensus Conference on the nomenclature of systemic vasculitis defined IgA vasculitis as “Vasculitis, with IgA1-dominant immune deposits, affecting small vessels (predominantly capillaries, venules, or arterioles). Often involves skin and gastrointestinal tract, and frequently causes arthritis. Glomerulonephritis indistinguishable from IgA nephropathy may occur” .
The ACR (1990) classification criteria (Table 12.1) have been widely used in clinical studies, but have relatively poor sensitivity (87.1 %) and specificity (87.7 %) . These criteria have recently been finalized for use in children by the European League Against Rheumatism, the Paediatric Rheumatology International Trials Organisation and the European Pediatric Rheumatology Society (Table 12.2) . There are no validated diagnostic criteria.
ACR classification criteria for IgA vasculitis (Henoch–Schönlein purpura)
Slightly elevated purpuric rash over one or more areas of the skin not related to thrombocytopaenia
Diffuse abdominal pain worse after meals, or bowel ischemia, usually bloody diarrhea
Age at onset <20 years
Development of first symptoms at age 20 years or less
Wall granulocytes on biopsy
Histological changes showing granulocytes in the walls of arteries or venules
EULAR/PRINTO/PReS classification criteria for childhood IgA vasculitis
Palpable purpura or petechiae (mandatory criterion) with lower limb predominance in the presence of at least one of the following four features:
Diffused abdominal pain
Any biopsy showing predominant IgA deposition
Arthritisa or arthralgia
Renal involvement (any hematuria and/or proteinuria)
IgA vasculitis is a predominantly childhood vasculitic syndrome. It is the most common vasculitis in children and can occur from 6 months of age onward. Most of the children are less than 10 years of age. There is no obvious gender predisposition. The incidence of IgA vasculitis in adults is lower than in children, and in the UK, the incidence is 20.4/100,000 children , and 1.3/100,000 adults over the age of 16 years .
The etiology of IgA vasculitis is unknown; however, there often appears to be a triggering upper respiratory infection especially in children. A number of drugs such as penicillin, erythromycin, and nonsteroidal anti-inflammatory drugs have been implicated as triggers.
12.5 Clinical Features
The classical features of IgA vasculitis are a triad of rash, gastrointestinal upset, and joint pain.
The classical rash of IgA vasculitis is usually the first sign of the disease  (Figs. 12.1 and 12.2). It is an erythematous papular rash which develops into a palpable purpura. The usual distribution is on the dependent and pressure-bearing areas of the lower limbs and buttocks. The purpura may be preceded by an urticarial rash. The rash is usually symmetrical and does not blanch with pressure. Skin necrosis may be seen in areas of severe cutaneous hemorrhage, and is more common in adults.
Purpuric lesions on the legs of a patient with Henoch–Schönlein purpura. Note the lesions along the pressure line caused by the patient’s socks
Purpuric lesions on the abdomen in a patient with Henoch–Schönlein purpura
The rash can be accompanied with gastrointestinal manifestations including abdominal pain, nausea, and vomiting. Abdominal pain is perhaps the second most frequent clinical manifestation after the skin rash. It is frequently colicky, and the severity may wax and wane in relation with new crops of skin lesions. The pain is thought to be due to submucosal hemorrhages. These can produce GI bleeds which can manifest as hematemesis or malaena. Infrequently acute intussusception has been observed in children.