ACAAI: New Insight into Peanut Allergy

PHILADELPHIA, Nov. 12 -- In patients with refractory allergic eye diseases, the cause of the irritation could be peanuts, researchers reported here.

Among patients with allergic eye diseases who were unresponsive to treatment and had no relief of symptoms from standard therapies, a peanut-elimination diet followed by a peanut challenge resulted in moderate to severe symptoms scores, reported Blanca E. del Ro-Navarro, M.D., from the Hospital Infantil de Mexico, Federico Gomez, in Mexico City, and colleagues.

The 25-patient study is the first to find a link between allergic keratoconjunctivitis and food allergy, the authors asserted in a poster presentation at the American College of Allergy, Ashtma & Immunology meeting here. Peanuts had been associated with allergic eye disease previously in 20% of the cases.

"Peanut allergy is the most serious of the hypersensitivity reactions to foods due to its persistence and high risk of severe anaphylaxis," the authors wrote.

They tested for peanut allergy all patients (mean age eight, range 3-18) who came to their hospital with allergic eye disease during 2005. Diagnoses included allergic keratoconjunctivitis in 11 patients, vernal keratoconjunctivitis in six, and perennial allergic conjunctivitis in eight.

All patients had been previously treated by an ophthalmologist with the therapy indicated for their diagnoses.

The patients were tested for sensitivity with skin prick and patch testing, and were then put on peanut-free diets for two weeks. They were then challenged openly with peanut allergen in two session two weeks apart.

The patients were evaluated for symptoms score on a scale of 0 to 15, with 0 being asymptomatic, and 12 being highly symptomatic, both before and after the challenge. The scores were calculated by assigning scores of 0 (symptoms absent) to 3 (severe) for each of four symptoms -- tearing, itching, discharge, and photophobia -- and combining the scores.

The authors found that the mean symptom score at baseline was 8 (range 4-11), but just 2.2 (range 0-6) after two weeks on a peanut-free diet. When they were challenged again with peanut antigen, the mean symptoms core returned to the baseline level of 8 (range 3-12).

We found a 20% rate of peanut allergy in this group of patients, with the same rate that has been previously mentioned in other reports," the investigators wrote. "It is of particular interest that these patients were not responding to treatment and had no relief of their ocular symptoms, but with elimination diet their symptoms improved."

The authors noted that more studies with larger sample sizes will be needed to confirm their findings.