Page 171 - The Vasculitides, Volume 1: General Considerations and Systemic Vasculitis

Classification of Pediatric Vasculitides 147

of age [25]. The disease is less severe in children than in adults [26]. To fulfill ACR
classification criteria for HSP/IgAV, two of the following were required including, age less
than 20 years, palpable purpura, abdominal pain, and vessel wall granulocytes on biopsy [18].
During the revision process, the major change for children was making palpable purpura a
mandatory criterion [22]. The biopsy criterion was also revised as the presence of IgA
deposits in any biopsy increased the specificity of the criterion in children. It is important to
define IgA deposits as “predominant” to differentiate HSP/IgAV from other diseases with
IgA deposits [22, 24]. Moreover, it was agreed to use the United Nations/United Nations
Children?s Fund (UNICEF) definition of a “child” as an individual of age 18 years or less
[27], thus the age criterion in HSP/IgAV was deleted [22].

As joint involvement was more common in children, it was added to the group of criteria
[24]. Since renal involvement is a major factor in short- and long-term prognosis of HSP/
IgAV approximately 40% of children developing nephritis within six weeks of presentation
[28], renal involvement was considered a new criterion [24].

In its final form, the Ankara 2008 criteria for HSP/IgAV required the presence of
palpable purpura with lower limb predominance plus one of the following four features
including, diffuse abdominal pain, any biopsy showing predominant IgA deposition, arthritis
or arthralgia, and renal involvement as indicated by hematuria or proteinuria. If purpura was
of atypical distribution, the demonstration of IgA deposits in a biopsy was required [24].
These criteria achieved a sensitivity of 100% and a sensitivity of 87% in children [24].

Medium Vessel Vasculitis

Kawasaki Disease

KD is an acute, self-limited systemic vasculitis of medium- and small-sized vessels
occurring predominantly in children age 6 months to 5 years [29]. It is the second commonest
childhood vasculitis [30] and the leading cause of acquired childhood heart disease in
developed countries [31]. The distribution is worldwide with an incidence in Japanese
populations 10 to 15-fold greater than in Caucasians [5]. Before revision of the criteria for
KD, the classification was based either on Japanese or American classifications [32, 33].
The former required the presence of five of the following six criteria including, characteristic
fever, bilateral conjunctivitis, changes in lips and oral cavity, polymorphous exanthema,
changes of peripheral extremities and cervical lymphadenopathy [32]. The American
classification required fever plus four of the remaining five criteria [33].

The major complication of KD is damage to coronary arteries, and while 25% of
untreated KD patients suffer from coronary artery aneurysm, this decreases to 4% with proper
treatment [33]. As a consequence of the importance of coronary artery disease, it was agreed
that a child with typical echocardiographic changes could be classified as KD without
fulfilling four of the remaining criteria [24].

The second modification was the addition of the frequent finding of perianal
desquamation to the criterion of changes in the extremities [22]. After these modifications,
the classification criteria for KD were the mandatory criterion of fever persisting for at least
five days plus four of the following five including, changes in the peripheral extremities or

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