History and exam

Key diagnostic factors

common

presence of risk factors

Key risk factors include male sex, age between 2 and 10 years, and history of prior upper respiratory tract infection.

rash

Skin lesions are characterised as palpable purpura and are typically non-blanching.[Figure caption and citation for the preceding image starts]: Palpable purpura on the lower extremities of a childFrom the collection of Paul F. Roberts, MD [Citation ends].com.bmj.content.model.Caption@5eb478c1

The lesions are usually 2 to 10 mm in diameter, and represent the extravasation of blood into the skin. Lesions usually occur in crops and fade over several days to weeks and are typically concentrated on the legs and buttocks. The rash of IgAV occurs in all patients, but may not be the first presenting sign.

arthralgias

Can be present, often associated with oedema; the knees and ankles are most often affected.

Present in about 80% of patients. Generally do not cause any long-term problems.

abdominal pain

Occurs in about half of patients, often associated with nausea and vomiting.

signs of renal disease

Occurs in about 40% to 50% of patients, and can vary from mild (i.e., asymptomatic haematuria and/or proteinuria) to severe (i.e., rapidly progressive nephritis, nephrotic syndrome, and renal failure). It can produce microscopic haematuria, proteinuria, and RBC casts.[21]

Other diagnostic factors

uncommon

drug history

Some cases of IgAV are drug-related (e.g., penicillin, cefaclor, minocycline, hydralazine, and phenytoin); however, this is more common in adults.[19][20]​​

scrotal pain or swelling

Occurs in about 13% of boys with IgAV.[9]

headaches

This is a rare manifestation.

seizures

This is a rare manifestation.

pulmonary haemorrhage

This is a rare manifestation.

Risk factors

strong

genetics

Human leukocyte antigen subtypes and genes encoding host defence mechanisms are associated with a predisposition to developing the condition.[7]​ Geographical variation in the incidence of IgAV also suggests genetics may play a role.[7]

allergy

A history of allergy, including food allergies and atopic conditions, has been reported as a predisposing factor.[24][25][26]

male sex

Males are more often affected than females at a ratio of up to 2:1.[12]

age 2 to 10 years

IgAV can occur at any age but is mainly a disease of childhood that occurs predominantly between the ages of 2 and 10 years. Peak incidence is between 4 and 7 years.[11]

increasing age at onset

A risk factor for poor prognosis in children.[16][27]

In a retrospective cohort study conducted in Taiwan, risk of developing corticosteroid dependence, refractory disease, and renal involvement increased with increasing age at IgAV onset (particularly when onset age >6.5 years).[16]

winter season/prior infection

There is a striking seasonal variation in presentation of IgAV. Most cases occur in the autumn, winter, and early spring and often follow an upper respiratory tract infection, especially streptococcal infections.​​​[14][15]​​[17]

weak

medication

Some cases of IgAV are drug related (including penicillin, cefaclor, minocycline, hydralazine, and phenytoin); this is more common in adults.[19][20]​​

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