Bruise detection and visibility under alternate light during the first three days post-trauma

Cutaneous bruises are often hard to detect particularly on individuals with a darker complexion. Researchers and federal agencies have recommended the use of alternate light to aide in the assessment of subtle injury. However, studies are limited in their evaluation of wavelength performance during the first few days of bruise healing. The purpose of this pilot study was to examine whether an alternate light source (ALS) improves detection of bruises when compared to normal light typical of clinical practice during the first three days following induction.

A sample of eight healthy adults between 22 and 36 years of age with diverse skin color were recruited for this study. One bruise was induced on each participant by dropping a 4-oz (113g) steel ball through a 5-ft (1.5 m) vertical pipe onto the anterior surface of the forearm. Using the ALS, bruises were assessed under 14 different combinations of ultraviolet and short narrowband visible wavelengths and filters along with overhead fluorescent "examination" lighting. Participants were examined 3 to 4 times per day at approximately 4-h intervals for three consecutive days post induction.

Repeated bruise assessments on 8 subjects resulted in 59 bruise assessments and 885 total observations under the different wavelengths and filters combinations. A bruise was detectable in 46 (78%) of the assessments, with bruise ages ranging from 30 min to 57 h. Twenty (34%) bruises not detectable under normal light were visible with ASL. Multilevel modeling revealed a strong association between time and detection for shorter wavelengths, such as 365 nm (ultraviolet) and 450 nm.

The results of our study suggest alternate light is more likely to detect faint bruises than normal lighting during the first three days post injury. However, more research is needed to determine which wavelengths and filter combinations are most effective during that time frame.