Edema as a Key Presentation of Acrodermatitis Chronica Atrophicans: A Retrospective Cohort Study from a Tertiary...

Background/Objectives: Acrodermatitis chronica atrophicans (ACA), a late cutaneous manifestation of Lyme borreliosis, presents with a broad clinical spectrum. Most commonly, a characteristic bluish-red patchy rash, but it can also appear as unilateral limb swelling. This study aimed to characterize the clinical manifestations, diagnostic workup, and outcomes of patients with ACA in a tertiary setting in Denmark. Methods: Retrospective cohort study including all patients diagnosed with ACA at Copenhagen University Hospital-Rigshospitalet between 2017 and 2025. Results: Forty patients were included (median age 57 years; 63% female), with a median BMI of 24.5 [range 15.6-36.3]. Symptom duration was long (median 1 year). All patients presented with a skin rash. The most common location was the lower extremity, 26/40 (65%). Local edema and neuropathic pain were common (20/40) 50% and (23/40) 55%, respectively. A total of 13/40 patients underwent lymphoscintigraphy, which was deemed pathological in 7/13 (54%). The patients presenting with edema underwent significantly more imaging procedures, median 3 (range 1-5) vs. 0 (range 0-2), p < 0.005; they were younger, median age 49 years (range 17-76) vs. median 65 (range 30-81), p = 0.03; but did not differ in BMI, median 26.6 (range 19.0-36.2) versus median 23.8 (range 15.6-36.3), p = 0.48. All patients were Borrelia burgdorferi (Bb) IgG seropositive. Borrelia-specific PCR was positive in 6/13 (46%). Histopathology supported the diagnosis in 19/20 (95%). Clinical evaluation of the treatment response at 3 months was good in 33/40 (83%). Conclusions: Edema/swelling due to lymphatic obstruction is a common presentation of ACA in the tertiary setting, resulting in extensive diagnostic workup. The condition is associated with younger age but not BMI, sex, or immunodeficiency. Raised awareness and earlier testing for Bb IgG in serum seem warranted.