Pollen sensitization occurs through contact with respiratory allergens. Anaphylactic shock or urticaria induced by pollen ingestion has been described in cases of atopy [1]. Hemolytic anemia has occurred after ingestion of plants or drugs containing flavonoids [2-4]. We report what we believe to be the first case of immunoallergic hemolytic anemia after repeated self-administration of pollen.

A 45-year-old woman had venous insufficiency treated in 1994 by troxerutine, 3500 mg. She had eaten royal jelly for 5 years and had eaten pollen grains for 2 weeks of the year for 2 years. In October 1996, transient fever, arthralgia, and lumbar pain developed after she ingested 15 g of pollen. A similar episode occurred 1 week later after a second ingestion. Two hours after a third ingestion, sudden pain developed in the back and abdomen, with fever, fatigue, jaundice, and dark urine. Anemia (iron level, 6.7 g/dL) with macrocytosis (120 fL) but no schizocytes was detected; leukocyte count was 38.5 g/L, thrombocyte count was 118 g/L, prothrombin time was 18.7 seconds (for a free hemoglobin level of 12.4 µmol/L), fibrinogen level was 1.2 g/L, level of products of fibrinogen degradation was 640 µg/mL, free hemoglobin level was 220 µmol/L, total bilirubin level was 95 mg/L (free bilirubin level, 94 mg/L), and haptoglobin level was 0.08 g/L. Electrophoresis for hemoglobinemia had normal results. No deficiency of G6PD or pyruvate kinase was found. Result of the Coombs test was positive for IgG and complement, and circulating immune complexes were found. Aspartate aminotransferase level was 340 IU/L, alanine aminotransferase level was 101 IU/L, blood urea nitrogen level was 19.98 mmol/L, and serum creatinine level was 291.7 µmol/L.

Methylprednisolone and 8 units of packed red blood cells were given, and plasma exchange was done with five sessions of hemodialysis. Hemostasis improved in 2 days, results of hepatic function tests returned to normal in 4 days, and hemodialysis was stopped 10 days later. The patient was discharged with moderate renal insufficiency 21 days after symptom onset. At 2-month follow-up, recovery was total.

Analysis of the pollen showed a heterogenous mixture of pure pollen. Results of skin-prick tests (done with total pollen, purified pollen, and routine airborne allergens) were negative. Tests for IgE and specific IgE reaction to graminae, tree, and herbacea pollen had negative results. The recurrent episodes and the positive result on the Coombs test suggested an immunoallergic reaction. The patient did not have atopy or autoimmune systemic disease, and she was not receiving any drugs. This sensitization was IgG-mediated, incriminating the ingested pollen.