Is lymphangitic streaking associated with different pathogens?

Objectives: Little is known regarding the differences in microbiology associated with cellulitis or abscess with or without lymphangitic streaking. The objective of our study is to assess whether there are differences in the pathogens identified from wound cultures of patients with paronychia with and without associated lymphangitis.

Methods: Retrospective cross-sectional study at a tertiary pediatric emergency department over 25 years. We opted to assess patients with paronychia of the finger, assuming that these cases will have a greater variety of causative pathogens compared to other cases of cellulitis and soft tissue abscess that are associated with nail biting. Case identification was conducted using a computerized text-screening search that was refined by manual chart review. We included patients from 1 month to 20 years of age who underwent an incision and drainage (I&D) of a paronychia and had a culture obtained. The presence or absence of lymphangitis was determined from the clinical narrative in the medical record. We excluded patients treated with antibiotics prior to I&D as well as immune-compromised patients. We used descriptive statistics for prevalence and χ2 tests for categorical variables.

Results: Two hundred sixty-six patients met inclusion criteria. The median age was 9.7 years [IQR 4.7, 15.4] and 45.1% were female. Twenty-two patients (8.3%) had lymphangitic streaking associated with their paronychia. Patients with lymphangitis streaking were similar to those without lymphangitis in terms of age and sex (p = 0.52 and p = 0.82, respectively). Overall, the predominant bacteria was MSSA (40%) followed by MRSA (26%). No significant differences were found between the pathogens in the 22 patients with associated lymphangitis compared to the 244 patients without.

Conclusion: Staphylococcus aureus represent the majority of pathogens in paronychia, although streptococcal species and gram-negative bacteria were also common. Among patients with paronychia of the finger, there seems to be no association between pathogen type and presence of lymphangitic streaking.