Table 4.

Studies evaluating water and temperature exposure.

Study	Number of Participants	Exposure	Results
Water Exposure
Firooz et al. 2015 [24]	20	Water immersion at 15–20 °C for 30 min a day for five days	TEWL increased pH increased
Agner et al. 1993 [32]	14	Water patch-occlusion during 24 h: -One closed patch test with 60 uL of an aqueous solution of 0.5% SLS on a filter disc. -One closed patch test with 60 uL sterile water on a filter disc. -One empty chamber	TEWL increased immediately and 30 min after removal of all test chambers. TEWL also increased 180 min after SLS and water patch removal.
Our study	50	Cold water exposure (11.13 (2.71 SD) °C) for 10 min	Temperature decreased by 6.69 °C pH increased by 0.29 TEWL increased by 9.21 (g·h−1·m−2) SCH increased 3.86 AU
		Hot water exposure (41.29 (2.29 SD) °C) for 10 min	Temperature increased by 2.42 °C pH increased by by 0.32 Erythema increased by 36.88 AU TEWL increased by 32.83 (g·h−1·m−2)
Temperature exposure
Kim et al. 2019 [16]	20	Exposure to outdoor environment for 90 min (34.76 ± 2.79 °C, 53.13 ± 8.78% RH)	SCH on the forearm and sebum secretion on the face increased. SCH and TEWL on the cheek and greasiness on the forearm and the forehead decreased. pH decreased in the face and the forearm.
		Exposure to indoor environment for 90 min (22.97 ± 0.74 °C, 53.14 ± 2.37% RH)	SCH in the forehead and the forearm. Sebum secretion and greasiness on the face increased. TEWL and pH in the face and the forearm decreased.
Cravello et al. 2008 [26]	6	Exposure to three levels of ambient temperature (20 °C, 25 °C and 30 °C) and four levels of RH (25%, 45%, 65% and 85%)	TEWL is positively correlated to ambient temperature. Skin temperature is correlated positively to ambient temperature but not to RH. SCH is strongly affected by ambient temperature and RH.
Qiu et al. 2011 [35]	354	6 month periods, summer (35–40 °C, RH ≥ 70%) and winter (0–5 °C, RH ≥ 70%)	SCH and melanin increased in summer compared to winter.
Our study	50	Cold temperatrue exposure (4 °C)	Temperature decreased by 5.41 °C
		Hot temperature exposure (44 °C)	Temperatrure increased by 1.69 °C Erythema increased by 17.34 AU TEWL increased by 1.98 (g·h−1·m−2)

AU, arbitrary units; RH, relative humidity; SCH, stratum corneum hydration; SLS, sodium lauryl sulphate; TEWL, transepidermal water loss.