Core temperature affects scalp skin temperature during scalp cooling

Background: The efficacy of hair loss prevention by scalp cooling to prevent chemotherapy induced hair loss has been shown to be related to scalp skin temperature. Scalp skin temperature, however, is dependent not only on local cooling but also on the thermal status of the body. Objectives: This study was conducted to investigate the effect of body temperature on scalp skin temperature. Methods: We conducted experiments in which 13 healthy subjects consumed ice slurry to lower body temperature for 15 minutes after the start of scalp cooling and then performed two 12-minute cycle exercise sessions to increase body core temperature. Esophageal temperature (T<inf>es</inf>), rectal temperature (T<inf>re</inf>), mean skin temperature (eight locations, T<inf>skin</inf>), and mean scalp temperature (five locations, T<inf>scalp</inf>) were recorded. Results: During the initial 10 minutes of scalp cooling, T<inf>scalp</inf> decreased by >15 °C, whereas T<inf>es</inf> decreased by 0.2 °C. After ice slurry ingestion, T<inf>es</inf>, T<inf>re</inf>, and T<inf>skin</inf> were 35.8, 36.5, and 31.3 °C, respectively, and increased after exercise to 36.3, 37.3, and 33.0 °C, respectively. T<inf>scalp</inf> was significantly correlated to T<inf>es</inf> (r = 0.39, P < 0.01): an increase of 1 °C in T<inf>es</inf> corresponded to an increase of 1.6 °C in T<inf>scalp</inf>. Conclusions: Slight cooling of patients with an elevated body temperature during scalp cooling contributes to the decrease in scalp temperature and may improve the prevention of hair loss. This may be useful if the desired decrease of scalp temperature cannot be obtained by scalp cooling systems.