Effect of Humor on Allergen-Induced Wheal Reactions Letters JAMA v.285 n.6, 14feb01

To the Editor: Norman Cousins¹ originally reported that only 10 minutes of laughter alleviated the pain of ankylosing spondyilitis. Subsequently, it has been reported that laughter during a 60-minute humorous video decreased blood cortisol levels and increased natural killer activity in healthy subjects.² Another study reported that exposure to a 60-minute rakugo (traditional Japanese comic story) decreased blood levels of interleukin 6 and interferon

and alleviated pain in patients with rheumatoid arthritis.³

Atopic dermatitis is a pruritic inflammatory skin disorder often associated with elevated allergen-specific IgE antibodies.⁴ I examined the effects of laughter on allergen-induced skin wheal responses in patients with atopic dermatitis.

Methods

After giving informed consent, 26 patients with atopic dermatitis (15 women and 11 men; mean age, 31 years; range, 21-58 years) were studied. All of the patients were allergic to house dust mites (Dermatophagoides pteronyssinus), and 23 and 21 patients were also allergic to cedar pollen and cat dander, respectively. The patients did not receive any medication for 72 hours prior to the study. Before and after viewing an 87-minute video (Modern Times, featuring Charlie Chaplin), skin prick tests were performed using commercial allergen extract and wheal size was measured 15 minutes later.⁴ The same procedure, but using only dust mite allergen, was then repeated before and after an 87-minute video featuring weather information.

Results

The wheal responses induced by house dust mite allergens were significantly (P<.01) reduced after viewing the humorous video (Figure 1), and this reduction was reversed after 4 hours but not after 2 hours (data not shown). Wheal responses to cedar pollen and cat dander were also significantly reduced after viewing the humorous video. The diameter (mean [SD]) of the wheal caused by cedar pollen was reduced from 8 (4) to 2 (2) mm (n = 23) and that caused by cat dander from 7 (3) to 2 (2) mm (n = 21). The wheal responses induced by house dust mite allergen were not significantly different before (11 [4] mm) or after (11 [5] mm) viewing the nonhumorous video.

Figure. Effect of Laughter on Wheal Responses Induced by House Dust Mite Allergen

Wheal responses induced by house dust mite (Dermatophagoides pteronyssinus) allergen were studied in 26 patients with atopic dermatitis by skin prick test before and after viewing Modern Times. Individual values of diameters of the wheal responses are reported. Solid circles indicate mean values; vertical bars, SDs.

Comment

This study is limited by the lack of blinding or randomization of crossover. Nonetheless, these results suggest that the induction of laughter may play some role in alleviating allergic diseases. The exact mechanism of reduction of wheal responses remains unknown.

Hajime Kimata, MD, PhD
Department of Allergy
Unitika Central Hospital
Uji-City, Kyoto Prefecture, Japan

1. Cousins N. Anatomy of an illness (as perceived by the patient). N Engl J Med. 1976;295:1458-1463. MEDLINE

2. Berk LS. Eustress of mirthful laughter modifies natural killer cell activity. Clin Res. 1989;37:115A.

3. Yoshino S, Fujimori J, Kohda M. Effects of mirthful laughter on neuroendocrine and immune systems in patients with rheumatoid arthritis. J Rheumatol. 1996;23:793-794. MEDLINE

4. Kimata H, Igarashi M. Inhibition of human allergic skin reactions in vivo by pretreatment with cromolyn (disodium cromoglycate). Allergy. 1990;45:393-395. MEDLINE