Karin Rydenman: Clinical features, epidemiology and disease burden of periodic fever (PFAPA) in children
Karin Rydenman’s thesis contributes new knowledge about the autoinflammatory disease PFAPA in children regarding its epidemiology, clinical presentation, disease burden and treatment outcomes. By identifying and diagnosing the condition, unnecessary investigations and antibiotic treatments can be reduced. The findings also highlight that PFAPA has a considerable impact on children’s quality of life and on the lives of their families, and that the disease course varies, with some children experiencing symptoms for a long time.
KARIN RYDENMAN
Dissertation defense: 28 May 2026 (click for details)
Doctoral thesis: Clinical and epidemiological aspects of periodic fever with aphthous stomatitis, pharyngitis and cervical adenitis (PFAPA)
Research area: : Pediatrics
Sahlgrenska Academy, The Institute of Clinical Sciences
PFAPA – periodic fever with aphthous stomatitis, pharyngitis and cervical adenitis (1)– is an autoinflammatory disease characterized by regularly recurring fever episodes and primarily affects children under five years of age. The exact cause of the disease is still not fully understood, but it is believed to result from an overactive innate immune system, leading to inflammation without an underlying infection.
“Much remains unclear about how the disease develops and how it should best be treated. Since the diagnosis is still relatively unfamiliar and the symptoms are easily mistaken for infections, it often takes a long time for children to receive the correct diagnosis,” says Karin Rydenman, pediatrician at the Department of Pediatrics, NU Hospital Group (NÄL and Uddevalla Hospital), and doctoral student at the Institute of Clinical Sciences.
Contributing to more nuanced management and improved clinical decision-making
In her thesis, she describes the clinical presentation of PFAPA in a large patient cohort, examining age at disease onset, the incidence of the disease, and the importance of identifying and diagnosing children with PFAPA in order to reduce unnecessary antibiotic use.
“We have also shown that the disease has a substantial impact on the quality of life of affected children and places a burden on the entire family. This impact decreases after tonsillectomy, that is, surgical removal of the tonsils. However, long-term outcomes after tonsillectomy varied, with persistent symptoms remaining in approximately one-third of the children (Figure 2).”
The findings may contribute to more nuanced clinical management and improved decision-making.
Figure 2 from the thesis: Schematic illustration of the clinical course after tonsillectomy in PFAPA. The number of patients in each node is shown in bold. At long-term follow-up after a median of 8.8 years (2.8–16.1), 37% of patients still experienced PFAPA symptoms.
What has been the most rewarding and most challenging aspect of the doctoral project?
“The most rewarding aspect has been combining clinical work with research and contributing to increased knowledge about an intriguing condition that has a major impact on the everyday lives of affected children and their families,” says Karin Rydenman, and continues:
“One challenge has been studying a disease without specific biomarkers and dealing with the fact that different diagnostic criteria are used in PFAPA research. It is also both rewarding and challenging to study a relatively rare and still poorly recognized disease. This means that the number of patients is limited, but it also means encountering great gratitude from families when they finally receive an explanation for their child’s symptoms, and many are eager to contribute to increasing knowledge about the disease.”
Text: Susanne Lj Westergren