Immunization and Bacterial Pathogens in the Oropharynx as Risk Factors for Alopecia Areata

The study conducted at the Dr Ladislao de la Pascua Dermatology Clinic in Mexico City between September 2008 and February 2009 included 65 patients with alopecia areata and 65 control patients. It found that a history of immunization had an odds ratio (OR) of 3.3 for being a risk factor for alopecia areata, while the presence of bacterial pathogens in the oropharynx had an OR of 2.6, and being a carrier of Streptococcus pyogenes had an OR of 2.1. The study concluded that both a history of immunization and throat carriage of bacterial pathogens are associated with an increased risk of alopecia areata, especially in patients with less than 25% hair loss and a disease duration of less than one year. However, the study did not establish a causal relationship and recommended further research, while also suggesting that patients with alopecia areata be evaluated for infectious agents.