Background/Purpose: Although the prognosis of
Henoch-Schönlein purpura (HSP) is usually favorable, relapses are relatively
frequent.

Objectives: Our
aim was to analyze the frequency, type and risk factors for relapses in a large
series of unselected patients with HSP.

Methods: Retrospective
study of 417 patients from a single center, diagnosed with HSP according to the
criteria proposed by Michel et al. (J Rheumatol 1992; 19: 721-28). Relapse was
defined as a new outbreak of HSP in a previously asymptomatic patient (at least
for one month). Quantitative variables were expressed as mean ± SD or as median
(interquartile range), and compared with the Student t-test or the Mann-Whitney
U-test, as appropriate. Dichotomous variables were expressed as percentages and
compared by using the chi-square test. The variables associated with HSP
relapse in the univariate analysis entered into a stepwise multivariate
logistic regression. Statistical analysis was performed using SPSS 15.0.

Results: 417
patients (240 men/177 women) were studied; median age, 7.5 years (IQR [5.3 to
20.1]). 315 (75.5%) were children or young people (≤20 years) and 102
(24.5%) adults. Clinical manifestations (onset/HSP established,%) were: skin
lesions (55.9/100), nephropathy (24/41.2), gastrointestinal involvement (13.7/64.5),
joint symptoms (9.1/63.1) and fever (6.2/20.4). Corticosteroids were the most
frequently used drugs (35%), followed by NSAIDs (14%), and cytotoxic agents
(5%).

After a median
follow-up of 12 (IQR [2-38]) months, complete recovery was observed in most cases
(n=346; 83.2%) and persistent and usually mild nephropathy, in 32 patients
(7.7%). Relapses occurred in almost one third of the patients (n=133; 31.9%).
Clinical manifestations during relapses were: cutaneous (89.6%); abdominal
(27.1%); renal (25.9%) and articular (16.8%). The median number of relapses was
2.4 (IQR [1-3]). The main risk factors for the development of HSP relapse in
univariate analysis are shown in the TABLE.

After
multivariate analyses the most powerful predictive factors for relapse were
joint manifestations at disease onset, gastrointestinal manifestations during
the course of the disease, and corticosteroid treatment at the time of the
first episode of HSP (TABLE).

Conclusion: HSP
is usually a benign entity but relapses are not uncommon. Patients with
articular symptoms at onset or presenting with gastrointestinal manifestations
during the course of the disease or those needing corticosteroids to control
the initial episode of HSP, are more prone to develop relapses.