Elevated serum tryptase levels in a patient with protracted anaphylaxis.

Background: Anaphylactic reactions usually occur seconds to minutes after exposure to the relevant antigen. Late onset, biphasic, and protracted anaphylaxis also occur. The incidence of prolonged responses is unknown, but may be common. In all nonfood-related cases, levels of tryptase were not measured during protracted episodes. Tryptase has been shown to be a useful specific indicator of mast cell involvement in anaphylaxis.

Objective: To determine whether mast cell activation, as demonstrated by elevated serum tryptase concentrations, can occur in protracted anaphylaxis.

Methods: Case report; serum tryptase concentrations were measured by radioimmunoassay.

Results: A 33-year-old white man developed hives three days prior to admission. The next day, vomiting, abdominal cramps and bloating, lower lip swelling, wheezing, and a feeling of tightness over his throat and chest were experienced. The gastrointestinal symptoms continued until his hospital admission. One day prior to admission, he developed transient lightheadedness. On admission he had generalized urticaria and abdominal tenderness. Blood pressure of 115/58 mm/Hg rose to 180/60 and heart rate fell from 107/min to 90/min following 2.2 L of intravenous fluids. Serum tryptase levels were elevated at 7.2 ng/mL and 5.1 ng/mL on the first and second hospital days (fourth and fifth days of symptoms). Serum tryptase was < 1.0 ng/mL 5 months later.

Conclusions: The elevated serum tryptase levels at 96 and 120 hours following the onset of symptoms strongly suggest that continued mast cell degranulation can occur during protracted anaphylaxis. This strengthens the argument that mast cell activation is important in the pathophysiology of protracted anaphylaxis.