**4. Clinical manifestation**

*Digestive System - Recent Advances*

the pediatric patients) [3].

intestinal tract) [5].

**2. Epidemiology**

**3. Pathogenesis**

upper respiratory tract infection [10].

severe in adults than in children [10].

the underlying cause remains unknown.

skin, the gastrointestinal (GI) tract, the kidneys, and the joints; it is an acute IgAmediated disorder that rarely may affect the lungs and the central nervous system (CNS) [2]. IgA vasculitis is a multi-system disorder characterized by palpable purpura, arthritis, glomerulonephritis, and gastrointestinal manifestations and is the most common form of systemic vasculitis for children (90% of cases occur in

Although a lot of algorithm diagnoses were proposed (The American College of Rheumatology, Michel's criteria, Chapel Hill Consensus Conference, etc.) [1], the diagnostic criteria remain the one published in 2006 [4], revised by the European League Against Rheumatism/Pediatric Rheumatology International Trial Organization/Pediatric Rheumatology European Society (EULAR/PRINTO/ PRES); the mandatory criterion is palpable purpura in association with at least one of the following: diffuse abdominal pain, arthritis or arthralgia, renal involvement (hematuria and/or proteinuria), and IgA deposition in biopsy specimen (skin,

Differential diagnosis includes many diseases with systemic manifestations (cutaneous, articular, gastrointestinal, renal) such as Crohn's disease (no palpable purpura or gastrointestinal bleeding), IgA nephropathy (no palpable purpura), and

IgA vasculitis is the most common vasculitis for children; it is usually seen in children between 3 and 10 years old (the age peak is 5–7 years) and very rarely in adults [3, 4]. The annual incidence varies greatly, from 13 to 20/100,000 for children to 0.8–1.8/100,000 for adults [6–8]. Demographic data showed that males are more frequently affected (male-to-female ratio varies from 1.2:1 to 1.8:1) [3, 9]. The diagnosis is more commonly established in winter and spring and rarely in summer [7, 8], and this aspect may be explained by the association of this disease with infection factors, while approximately 50% of IgA cases are preceded by an

Clinical features and severity of the disease also differ by aging, being more

IgA vasculitis is a small-vessel vasculitis syndrome involving the small vessels of the skin, gastrointestinal tract, kidneys, and joints, consisting of palpable purpura,

The etiology is still unknown, but precipitating factors such as drug intake and/ or upper respiratory tract infections have been associated with the disease development [11]. Although a variety of infectious and chemical triggers are recognized,

Other cases of IgA vasculitis have been associated with several viral infections or

In approximately two-thirds of the cases, typical symptoms occur after 7–14 days from an upper respiratory tract infection (previous epidemiological studies have found a seasonal variation of incidence in IgA vasculitis, with more cases occurring in autumn and winter related with upper respiratory tract infec-

vaccinations, foods, drugs, hematological malignancies, and tumors [4].

hypersensitivity vasculitis (absence of IgA deposition) [4].

arthralgia, and gastrointestinal and renal manifestations.

**36**

tion) [4, 11].

IgA vasculitis typically has a prodrome (headache, anorexia, fever); after that, a lot of symptoms may develop: rash (especially involving the legs), abdominal pain and vomiting, joint pain (especially involving the knees and ankles), subcutaneous edema, scrotal edema, etc.

The classic tetrad symptoms are rash, arthralgia/arthritis, abdominal pain, and renal manifestations. The clinical diagnosis is easily made in the presence of all these symptoms but may be omitted when the clinical picture is incomplete; in the absence of the classic purpuric rash, the diagnosis of Ig A vasculitis may not be obvious [14, 15].

Purpura and joint pain are usually the main symptoms on admission, but the symptoms may develop over the course of some days to weeks and may vary in their order of presentation.

The major clinical manifestations are the following:


#### **4.1 Skin manifestation**

The skin lesions are the earliest and most common appearance of the disease in the majority of patients (70%) and include palpable nonthrombocytopenic purpura which evolves from erythema to papules and then to non-blanching palpable purpura with petechiae and ecchymosis (**Figure 1**). The rash is the hallmark of the disease and typically appears in crops, with new crops appearing in waves (eruptions usually last an average of 3 weeks).

**Figure 1.** *Palpable purpura on both ankles.*

The typical rash is symmetrically distributed and located primarily in gravity-/ pressure-dependent areas, such as the feet, ankles, and lower legs in adults; in the case of children, the buttocks, face, trunk, and upper extremities are more affected [19]. In child patients purpura gradually disappears (it can recur and become chronic), but in adults, it may be necrotic or hemorrhagic in 1/3 of cases, and cutaneous exacerbations may be seen for 6 months or longer [20, 21].
