Anemia Linked to Body Lice Infestation

The association between body lice infestation and hemoglobin is investigated.

Body lice infestation was associated with lower hemoglobin levels and anemia, according to findings in a research letter discussing a retrospective, exposed-unexposed study that was published in JAMA Dermatology.

Investigators included hospitalized adults who received a dermatology consult from November 2017 to April 2021. They compared mean admission hemoglobin levels in patients with and without body lice matched in a 1:3 ratio for age, sex, and housing status. They used a paired t test to compare mean hemoglobin levels, and multiple linear regression tests adjusted for confounders to examine the association between body lice infestation and hemoglobin level. The primary outcome was mean hemoglobin level at hospital admission.

There were 27 patients with body lice and 81 without body lice included in the study. The mean age was 53.8 years, 18.5% were women, and 85.2% were homeless.

Patients with body lice infestation had significantly lower mean hemoglobin levels (10.4 g/dL) compared with those without body lice infestation (12.9 g/dL; P <.001). After adjusting for confounders, body lice infestation was associated with a 2.5 g/dL lower hemoglobin level (95% CI, 1.4-3.5 g/dL; P <.001). The percentage of patients with anemia was higher among patients with body lice (70.4%; 95% CI, 50-85%) than those without body lice (46.9%; 95% CI, 36.2-57.9%; P =.03).

The study was limited by referral bias, lack of data to evaluate for iron-deficiency anemia, and the small cohort size.

This study, combined with other research, highlights anemia as a possible systemic complication of body lice, and its prevalence among homeless patients emphasizes the need for clinical recommendations and public health interventions to reduce the risk forbody lice infestation, the study authors wrote.


Rudd N, Zakaria A, Kohn MA, et al. Association of body lice infestation with hemoglobin values in hospitalized dermatology patients. JAMA Dermatol. Published online April 20, 2022. doi:10.1001/jamadermatol.2022.0818