Bacterial Infections Involved in Certain Pediatric Psoriasis Subtypes, Study Suggests

New research is shedding light on the link between bacterial infections and psoriasis in pediatric patients, especially those with guttate or inverse psoriasis.1

Findings from the multicenter retrospective study suggest pediatric patients with guttate or inverse psoriasis may warrant evaluation for pharyngeal or anogenital bacterial infections—even if asymptomatic. Additionally, while bacteria like Streptococcus and Staphylococcus aureus were commonly isolated, treating the infection did not significantly alter psoriasis outcomes.1

A chronic, multisystem, inflammatory disease, psoriasis affects approximately 1% of children, with onset most common during adolescence. Although skin involvement often drives patients to seek medical care, recognizing the condition as a potentially multisystem disorder in the context of a complex interplay between genetic and environmental factors is crucial for optimizing disease management.2

“Guttate psoriasis onset and plaque psoriasis flares are associated with streptococcal pharyngitis,” Esteban Fernandez Faith, MD, a pediatric dermatologist, program director of the pediatric dermatology Fellowship at Nationwide Children’s Hospital, and an associate professor of pediatrics and dermatology at the Ohio State University College of Medicine and colleagues wrote.1 “Literature regarding the relationship between anogenital bacterial dermatitis and psoriasis in pediatric patients is limited.”

To address this gap in research, investigators conducted a multicenter retrospective study of patients ≤ 18 years of age seen at tertiary referral centers in the United States and Canada with an initial clinical encounter date between January 2011, and January 2021. For inclusion, patients were required to have a diagnosis of psoriasis or psoriasiform dermatitis identified by ICD-9 and ICD-10 codes and a microbiological test obtained to evaluate for a pharyngeal or anogenital infection.1

A total of 166 unique patients with psoriasis/psoriasiform dermatitis and suspected pharyngeal and/or anogenital infection met the inclusion criteria. The average age at initial evaluation was 9.2 ± 4.3 years with a slight female predominance (55%). The majority (66%) of subjects were White.1

Plaque psoriasis was observed in 49% of patients. Other subtypes of psoriasis seen in this population included guttate (36%), inverse (16%), pustular (4%), nail (4%), and erythrodermic (2%) psoriasis.1

Investigators noted 57% of patients had ≥ 1 positive culture. In total, 35 patients (21%) had a positive pharyngeal culture only, 53 (32%) had a positive anogenital culture only, and 6 patients (4%) had both positive cultures.1

Of the 59 patients with any positive anogenital culture, 53% grew Staphylococcus aureus, of which 77% were methicillin-sensitive Staphylococcus aureus, and 23% were methicillin-resistant Staphylococcus aureus. Additionally, 41% of positive anogenital cultures grew Streptococcus species.1

Investigators pointed out inverse psoriasis was significantly more common in patients with a positive anogenital culture than in those with a positive pharyngeal culture (adjusted P = .0356) or a negative pharyngeal and/or anogenital culture (adjusted P = .0356). They also noted guttate psoriasis was significantly more common in patients with a positive pharyngeal culture than in patients with a positive anogenital culture (adjusted P <.0001) or patients with a negative pharyngeal and/or anogenital culture (adjusted P = .0037).1

Of note, treatment of a positive bacterial culture did not correlate with the treatment response of psoriasis/psoriasiform dermatitis.1

“Pharyngeal and anogenital bacterial infections may be identified in pediatric patients with psoriasis, especially those with guttate and inverse psoriasis, respectively. Staphylococcus and Streptococcus are commonly identified pathogens in the anogenital areas of pediatric patients with psoriasis,” investigators concluded.1 “The multicenter design of this study has allowed us to gather and share important knowledge on the largest cohort of patients with an anogenital infection associated with psoriasis to date. Future prospective studies can further clarify the effect of treating a positive anogenital bacterial culture on psoriasis outcomes.”

References

1. Ravi M, Cordoro KM, Holland KE, et al. The Association of Psoriasis and Bacterial Infections in Pediatric Patients: A Retrospective Review. Pediatric Dermatology. https://doi.org/10.1111/pde.16007

2. Menter A, Cordoro KM, Davis DMR, et al. Joint American Academy of Dermatology–National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis in pediatric patients. JAAD. doi:10.1016/j.jaad.2019.08.049