History
Age of onset for acute hemorrhagic edema of infancy (AHEI) usually is 4-24 months but ranges from birth to 60 months. Clinical findings develop rapidly over 24-48 hours. Associated fever is common but tends to be low grade. Upper respiratory tract infection, gastroenteritis, medications (ie, antibiotics), or vaccination have been frequently reported to precede AHEI. [27, 28, 29, 30] Most cases occur in winter months.
Visceral and systemic involvement are uncommon but may include the following:
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Joint pain
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Abdominal pain, gastrointestinal tract bleeding, lethal intestinal complications (eg, intussusception) [25]
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Scrotal pain and testicular torsion [26]
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Periorbital edema [31]
A report of compartment syndrome has been described. [32]
Spontaneous recovery usually occurs within 1-3 weeks, [18] with a reported duration of up to 35 days. Episodes of AHEI may recur. [9]
Physical Examination
Patients usually are nontoxic in appearance. Characteristic, rosette-, annular-, or targetoid-shaped purpuric lesions are symmetrically distributed primarily on the face, ears, and extremities. [33, 34]
Purpura may involve the scrotum. [26, 35] Lesions may begin as urticarial plaques and enlarge up to 5 cm in diameter. The borders are sharp. Purpura of the umbilicus can be mistaken for the Cullen sign (a sign of possible intraperitoneal hemorrhage).

Mucosal involvement is rare but has been reported. [36]
Acral edema involving the dorsum of the hands and feet frequently extends proximally up the extremities. Edema is usually nontender and may be asymmetric. The scalp may be involved. Joint and abdominal examinations are usually unremarkable.

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Large cockade (rosette or knot of ribbons), annular, or targetoid purpuric lesions found primarily on the face, ears, and extremities are characteristic of acute hemorrhagic edema of infancy.
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The left leg in this patient with acute hemorrhagic edema of infancy is markedly more edematous than the right leg.
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Leukocytoclastic vasculitis and fibrinoid necrosis is seen in patients with acute hemorrhagic edema of infancy. This histologic pattern also is seen in Henoch-Schönlein purpura, although patients with Henoch-Schönlein purpura usually have immunoglobulin A deposition, and immunoglobulin A deposition is demonstrable in only approximately one third of patients with acute hemorrhagic edema of infancy (hematoxylin and eosin, magnification X40).
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This toddler with acute hemorrhagic edema of infancy has a discoloration in the area of the umbilicus similar to that described as Cullen sign.
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Note the concentric arcs of purpura on the patient's arm.
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Despite the frightening appearance of purpura in these patients, they usually are in no significant distress.