BOSTON – Patients with psoriasis are almost nine times more likely to have enlarged tonsils, compared with patients without psoriasis, according to the results of a small study.
"Our findings suggest that hypertrophic tonsils may be associated with a pathogenic role in psoriasis," Dr. Marianna Shvartsbeyn and her coinvestigators reported in a poster presented at the American Academy of Dermatology’s Summer Academy Meeting. But it is still too soon to know the clinical implications.
In all, 32 patients with psoriasis and 14 patients with noninflammatory skin conditions (common warts, melanoma, and nonmelanoma skin diseases) were recruited. Patients who previously underwent tonsillectomy were excluded.
Tonsils were examined by one investigator, using a 5-point standardized tonsillar hypertrophy grading scale (adopted from Am. Fam. Physician 2004;69:1147-55).
Tonsils that were entirely within the tonsillar fossa received a grade of 0. Tonsils occupying less than 25% of the lateral dimension of the oropharynx, as measured between the anterior tonsillar pillars, received a grade of 1; tonsils occupying less than 50% of the lateral dimension of the oropharynx were a 2; tonsils occupying less than 75% of the lateral dimension of the oropharynx were a 3; and tonsils occupying 75 % or more of the lateral dimension of the oropharynx received a grade of 4.
Chart reviews were conducted to collect information on patient age, sex, race, social history (tobacco, alcohol, and drug use), diagnosis of skin condition, and the duration/severity of disease, noted Dr. Shvartsbeyn and her colleague of the departments of pathology and dermatology at the New York University.
Patients with psoriasis were found to have had an odds ratio of 8.77 for having enlarged tonsils (grade 2 or greater), compared with healthy controls. Tonsillar size also was significantly larger in patients with psoriasis (mean tonsil grade, 1.78), than in control patients (mean tonsil grade, 0.86); the severity of psoriasis was positively associated with tonsil size, Dr. Shvartsbeyn and her colleagues reported.
Limited clinical data have suggested that there is an association between hypertrophic tonsils and inflammatory skin disease. Small studies have shown that among patients with psoriasis, the cutaneous lesions disappeared or improved after tonsillectomy. It is suspected that there may be a genetic predisposition that makes certain patient populations more susceptible, the researchers noted.
Histopathologic studies also point to the possible link between the robust immune response that takes place in the tonsils and the changes in the skin of patients with pustulosis palmaris et plantaris (PPP).
Histologic evaluation of tonsils obtained from patients with PPP has revealed enlargement of the secondary T nodules and atrophy of the lymph follicles, with a decrease in the number of the germinal center cells and fibrosis – changes typically seen in older tonsils. This finding provides indirect evidence of the intensely advanced stage of the immune response within the tonsils.
"Our hypothesis is that in chronic tonsillar hypertrophy, bacterial species that reside in the tonsils are released into the circulation and cause stimulation of T cells. As a result of this constant chronic stimulation, an autoreactive clone may be formed. The auto-clone may produce an antibody attacking the skin and drive inflammatory response. In some individuals, this exaggerated immune response may manifest as psoriasis," the investigators wrote.
And although there is empirical evidence "that tonsillectomy improved skin lesions in patients with psoriasis and pustulosis palmaris et plantaris in small retrospective studies, further studies are needed. ... The observed association needs validation and interventional study is needed to prove causation/contribution," Dr. Shvartsbeyn noted in an interview.
The study was supported by grants from the National Cancer Institute, the National Institute for Allergy and Infectious Diseases, and the National Institute of Dental and Craniofacial Research. The investigators did not report having any conflicts of interest.