COVID-19 vaccine associated axillary lymphadenopathy - A systematic review

; COVID-19 vaccines are commonly administered intramuscularly to the arm. Axillary lymphadenopathy has been reported as an adverse event after COVID-19 vaccination. In patients with breast cancers who received COVID-19 vaccination, presence of ipsilateral (or contralateral) lymphadenopathy poses diagnostic dilemma. This systematic review aims to evaluate the incidence and clinical characteristics of vaccine associated axillary lymphadenopathy.

; The systematic review was conducted with accordance to the PRISMA statement. The search terms used were "Vaccine" OR "Vaccination" AND "Lymphadenopathy" OR "Lymph node" AND "Covid-19″.

; 31 studies or reports were identified using the predefined keywords from the systematic review protocol. After excluding irrelevant papers (such as guidelines, reviews, opinions and commentaries), 10 studies or reports were included in the review.Pooled incidence of clinically detectable lymphadenopathy after COVID-19 vaccination was 91/22,532 (0.4%). Mean size of the vaccine associated axillary lymphadenopathy was 18.2 mm (Range 16 - 21 mm). Mean duration from vaccination to occurrence of axillary lymphadenopathy was 6.9 days (Range 2 - 18 days). In a study on 119 patients, enlarged axillary lymphadenopathy resolves in 4 to 5 weeks.

; Vaccine associated axillary lymphadenopathy is not uncommon. Management of it is based on multidisciplinary decision with patient demographics, vaccination history and radiological finding being taken into account. Additional imaging and biopsy may lead to unnecessary healthcare burden. Proper arrangement of vaccination and imaging regarding timing and laterality should be advocated to avoid confusion and patient anxiety.