Changes in atopy over 25 years

Editor—In the previous letter responding to the paper by Law et al on changes in atopy over time Linneberg asks whether the allergic epidemic has spread to old age.¹ We recently tried to answer a similar question by retrospectively reviewing our patients' records, the results having been presented as an abstract at the last annual meeting of the American Academy of Allergy, Asthma, Immunology.²

In the past five years 956 patients (306 male and 650 female) aged 60 and older (median 76, range 60-93) were referred to our allergy clinic for suspected atopic conditions. All of them underwent skin prick testing with the most common inhalant allergens, and 318 (33%) were found positive with a wheal of at least 3 mm, men being more often positive than women (40% (123/306) v 30% (195/650), P < 0.005).

The median age of these subjects was 65 (range 60-86). The allergen profile of skin positivity was similar in men and women and was characterised by a clear prevalence of pollens (78% (96/123) v 75% (147/195)) over dust mites (41% (51/123) v 36% (71/195)), animal danders (18% (22/123) v 16% (32/195)), and moulds (6% (7/123) v 8% (16/195)). Rhinitis (hay fever) was the most common complaint (74% (235/318)), whereas asthma was present in 33% (105/318). In 22% (70/318) the clinical onset of atopy was at or after their 60th birthday.

We conclude that atopy is spreading to old age. We need to be aware of this phenomenon so as not to underestimate the role of atopy in the respiratory conditions affecting elderly people. We will also need to draw specific guidelines for the management (allergen avoidance, pharmacological treatment, immunotherapy) of atopy in such patients, who often have important comorbidities.