Middle East Journal of Family Medicine

Correspondence to:
DR FAHAD ALANEZI,
Department of pediatrics,
Al-Jahra Hospital, Kuwait.
Tel: 9659846919 Email: fdh529@hotmail.com
.........................................................................................................................

ABSTRACT

Background: Henoch-Schonlein purpura is an IgA-mediated, autoimmune, hypersensitivity vasculitis of childhood characterized by purpuric rash occurring on the lower extremities, abdominal pain, arthritis and renal involvement. Although of unknown cause, HSP is often associated with infectious agents, food reactions, exposure to cold, insect bites and drug allergens. Ethnic variations of the rare childhood vasculitides are not well characterized. Our aim was to ascertain the incidence and presentation pattern in Arab children in Kuwait.

Patients and methods: Forty-four Arab children of 2-12 years old were included in this study. Detailed history was obtained, and through clinical examination was performed. Laboratory, as well as, imaging evaluation, was done.

Interpretation: Henoch-Schonlein purpura occurred more frequently among Arab children. The incidence was 0.3%. All patients presented with purpuric rash. Arthritis was present in 36.4%, and abdominal pain in 25% of cases. Renal involvement was rare. It occurred in 9% of cases. In contrary bleeding per rectum was common, it occurred in 20.4% of cases.

Keywords: Purpura, Henoch-Schonlein, systemic vasculitis of childhood, IgA-associated nephropathy, arthritis, abdominal pain.
..........................................................................................................................

This small- vessel vasculitis is most commonly seen in children. It is associated with abdominal pain and an acute arthritis affecting one or more joints at a time (1). Boys are affected twice as frequently as girls (2). It has an incidence of 14 per 100,000 children and occurs most frequently in spring and fall (3). Pulpable non-thrombocytopenic purpura is found characteristically over buttocks and lower legs, and up to half the children affected have angio-edema. Intussusception, rectal bleeding and renal involvement are features of more severe disease. Fewer than 54% of patients have acute renal insufficiency (4), and another 5% have slow progression with renal failure developing months to years later (5).

The skin lesions and the renal glomeruli may contain IgA immune complexes, which likely are formed in response to an inciting factor; most probably Parvovirus B19 (6). However the disease can occur secondary to other infectious agents, food reactions, exposure to cold, insect bites and drug allergies.
Ethnic differences in the incidence of childhood diseases are well recognized, and have been described for several conditions. Recognition of ethnic differences in incidence rates of rare conditions such as vasculitis, helps to identify the cause and directs the investigations. It can, as well, help in the planning of health services, and identification of outcome of these conditions.

The aim of this study was to find out the incidence and identify the presentation pattern of Henoch-Schonlein purpura (HSP) among Arab children in Kuwait.

Forty-four Arab children with Henoch-Schonlein purpura were included in this study. A child is considered to have HSP if he fulfils three or more out of the criteria of The American College of Rheumatology for the classification of Henoch-Schonlein purpura (1). Detailed history was obtained. History of recent drug ingestion and food consumption was ascertained. Abdominal pain and gastric hemorrhage had also been reported, as well as seizure activity. Full physical examination was performed. Skin rash, arthritis, throat congestion, palpable abdominal masses and signs of cardiac involvement were looked for and blood pressure was recorded.

Laboratory evaluation was done. This included CBC, ESR, LFT, PT & PTT, RFT, urinalysis, and stool for occult blood. Serum samples for C3, C4, ANA, ds DNA and rheumatoid factor were collected.
Ultra-sound abdomen was done in patients with abdominal pain. Renal biopsy was done in one case because of hematuria, heavy proteinuria and elevated blood pressure. Upper gastro-intestinal endoscopy was done in another case because of hematemesis.

Over a period of 2 years from January 2005 to December 2006; out of 16,903 admissions to Pediatric Department, Jahra Hospital 44 (0.3%) children had Henoch-Schonlein purpura. Twenty were males and 24 were females with a male to female ratio of 1:1.2 (Table 1). Their ages ranged from 2-12 years. The incidence was highest between 6 and 8 years (Figure 1), with a mean age of 6 years & 8 months. The mean age of male patients was 7 years (range 2.5-11 years.) and that of the females 6.5 yrs. (range 2-12 years). Twelve patients (27.2%) had recurrent attacks of HSP; 2 of them had more than one attack (Table 1).

All patients had purpuric skin rash mainly involving both lower limbs (Table 2). Arthritis was found in 16 (36.4%) patients, and abdominal pain in 11 (25%) patients. Six (13.6%) patients were edematous and only one (2.3%) patient had hypertension. Table 3 summarizes the clinical data.

Hematuria and proteinuria were present in 6 (13.5%) patients. Acute phase reactants were elevated in 25 (57%) patients and stools were positive for blood in 11 (25%) patients. Virology studies were positive in 11 (25%) cases; 2 Parvovirus, 1 EBV and 2 Adenovirus.

Ultrasound abdomen was normal in all patients. Renal biopsy showed minimal change; glomerulonephritis in one patient and gastroscopy revealed duodenitis with micro ulcers in another patient.

Henoch-Schonlein purpura is an acute vasculitis that affects children rarely. The etiology remains unknown, however circulating IgA immune complexes play a critical role in the pathogenesis of the disease. The prevalence of HSP peaks in children aged 3-10 years. It occurs twice as often in males as in females (7). Genetic contribution to childhood illness is likely to be increasingly recognized as our knowledge of the human genome becomes more sophisticated (8). Gander et al (2) noted important ethnic differences in the incidence rates for all childhood primary vasculitids. Their findings suggest a higher incidence of HSP in children below 14 years than, the 13.5-18/100,000, previously estimated (9, 10). They also found that the incidence rate of HSP was lower in blacks than any other population, a finding previously reported in black Americans (11). By comparison, results of a UK survey suggest an overall annual incidence of 1.9/100,000 in young children (12). In our study, we estimated an incidence of 0.3% (260/100,000), indicating that HSP among Arab Children may be more frequent. However, our incidence rate was among diseased children admitted to the hospital, not among the childhood population. The prevalence of the disease in our patients was similar to that found by others. It peaked in children aged 6-8 years (Figure1), but the male to female ratio was almost equal, 1:1.2.

Dermatological findings are notable in HSP. The rash is usually symmetrical and purpuric. It typically involves lower extremities and buttocks (13). In more severe cases, hemorrhagic or necrotic lesions may be prominent (14). All our cases presented with purpuric skin rash that involved lower limbs and buttocks. However, we noticed that the rash tends to be more generalized in children less than 4 years (Table 2), contrary to the findings of others who reported mild illness in infants and young children (7, 15, 16).

Joint symptoms occur in 70-85% of cases (17). They precede the rash in 25% of cases. Joints are warm, tender and swollen. In one study in Thailand, joints were affected in 42.6% of cases of childhood Henoch-Schonlein purpura (Pabunruang, 2002). In our study, only 36% of patients had arthritis. This may be due to ethnic susceptibility as gene polymorphism may contribute to the diversity of clinical responses to inflammatory stimulation.

The most serious sequelae of HSP is renal involvement. It occurs in 50% of older children, and 25% of children younger than 2 years (18, 19, 20). In our patients, only 4 (9%) presented with renal involvement; one (2.2%) of them had hypertension. Renal function was normal in all. This may be due to the fact that Arab children are less susceptible to renal involvement during the course of the disease. Other authors also reported ethnic differences for nephritis in HSP (21).

Gastro-intestinal manifestations, the commonest second manifestation of HSP, occur in more than 50% of cases and usually consist of colicky abdominal pain, melena, or bloody diarrhoea (22, 23). Hematemesis occurs less frequently. In our study, 11 (25%) patients had abdominal pain, 9 (20.4%) had bleeding per rectum, and one (2.2%) had hematemesis.

From the previous discussion, we can assume that ethnic differences play a role in susceptibility to HSP, as well as its presentation pattern. However, any estimates must be tentative as less severe cases may be missed. Also these differences may be secondary to differences in associated provocative or inducing factors among locations.