Sleep deprivation can increase emotional distress and mood disorders; reduce quality of life; and lead to cognitive, memory, and performance deficits.1 Military service predisposes members to disordered sleep due to the rigors of deployments and field training, such as long shifts, shift changes, stressful work environments, and time zone changes. Evidence shows that sleep deprivation is associated with cardiovascular disease, gastrointestinal disease, and some cancers.2 We explore multiple mechanisms by which sleep deprivation may affect the skin. We also review the potential impacts of sleep deprivation on specific topics in dermatology, including atopic dermatitis (AD), psoriasis, alopecia areata, physical attractiveness, wound healing, and skin cancer.
Sleep and Military Service
Approximately 35.2% of Americans experience short sleep duration, which the Centers for Disease Control and Prevention defines as sleeping fewer than 7 hours per 24-hour period.3 Short sleep duration is even more common among individuals working in protective services and the military (50.4%).4 United States military service members experience multiple contributors to disordered sleep, including combat operations, shift work, psychiatric disorders such as posttraumatic stress disorder, and traumatic brain injury.5 Bramoweth and Germain6 described the case of a 27-year-old man who served 2 combat tours as an infantryman in Afghanistan, during which time he routinely remained awake for more than 24 hours at a time due to night missions and extended operations. Even when he was not directly involved in combat operations, he was rarely able to keep a regular sleep schedule.6 Service members returning from deployment also report decreased sleep. In one study (N=2717), 43% of respondents reported short sleep duration (<7 hours of sleep per night) and 29% reported very short sleep duration (<6 hours of sleep per night).7 Even stateside, service members experience acute sleep deprivation during training.8
Sleep and Skin
The idea that skin conditions can affect quality of sleep is not controversial. Pruritus, pain, and emotional distress associated with different dermatologic conditions have all been implicated in adversely affecting sleep.9 Given the effects of sleep deprivation on other organ systems, it also can affect the skin. Possible mechanisms of action include negative effects of sleep deprivation on the hypothalamic-pituitary-adrenal (HPA) axis, cutaneous barrier function, and immune function. First, the HPA axis activity follows a circadian rhythm.10 Activation outside of the bounds of this normal rhythm can have adverse effects on sleep. Alternatively, sleep deprivation and decreased sleep quality can negatively affect the HPA axis.10 These changes can adversely affect cutaneous barrier and immune function.11 Cutaneous barrier function is vitally important in the context of inflammatory dermatologic conditions. Transepidermal water loss, a measurement used to estimate cutaneous barrier function, is increased by sleep deprivation.12 Finally, the cutaneous immune system is an important component of inflammatory dermatologic conditions, cancer immune surveillance, and wound healing, and it also is negatively impacted by sleep deprivation.13 This framework of sleep deprivation affecting the HPA axis, cutaneous barrier function, and cutaneous immune function will help to guide the following discussion on the effects of decreased sleep on specific dermatologic conditions.
Atopic Dermatitis—Individuals with AD are at higher odds of having insomnia, fatigue, and overall poorer health status, including more sick days and increased visits to a physician.14 Additionally, it is possible that the relationship between AD and sleep is not unidirectional. Chang and Chiang15 discussed the possibility of sleep disturbances contributing to AD flares and listed 3 possible mechanisms by which sleep disturbance could potentially flare AD: exacerbation of the itch-scratch cycle; changes in the immune system, including a possible shift to helper T cell (TH2) dominance; and worsening of chronic stress in patients with AD. These changes may lead to a vicious cycle of impaired sleep and AD exacerbations. It may be helpful to view sleep impairment and AD as comorbid conditions requiring co-management for optimal outcomes. This perspective has military relevance because even without considering sleep deprivation, deployment and field conditions are known to increase the risk for AD flares.16
Psoriasis—Psoriasis also may have a bidirectional relationship with sleep. A study utilizing data from the Nurses’ Health Study showed that working a night shift increased the risk for psoriasis.17 Importantly, this connection is associative and not causative. It is possible that other factors in those who worked night shifts such as probable decreased UV exposure or reported increased body mass index played a role. Studies using psoriasis mice models have shown increased inflammation with sleep deprivation.18 Another possible connection is the effect of sleep deprivation on the gut microbiome. Sleep dysfunction is associated with altered gut bacteria ratios, and similar gut bacteria ratios were found in patients with psoriasis, which may indicate an association between sleep deprivation and psoriasis disease progression.19 There also is an increased association of obstructive sleep apnea in patients with psoriasis compared to the general population.20 Fortunately, the rate of consultations for psoriasis in deployed soldiers in the last several conflicts has been quite low, making up only 2.1% of diagnosed dermatologic conditions,21 which is because service members with moderate to severe psoriasis likely will not be deployed.
Alopecia Areata—Alopecia areata also may be associated with sleep deprivation. A large retrospective cohort study looking at the risk for alopecia in patients with sleep disorders showed that a sleep disorder was an independent risk factor for alopecia areata.22 The impact of sleep on the HPA axis portrays a possible mechanism for the negative effects of sleep deprivation on the immune system. Interestingly, in this study, the association was strongest for the 0- to 24-year-old age group. According to the 2020 demographics profile of the military community, 45% of active-duty personnel are 25 years or younger.23 Fortunately, although alopecia areata can be a distressing condition, it should not have much effect on military readiness, as most individuals with this diagnosis are still deployable.
Physical Appearance—Studies where raters evaluate photographs of sleep-deprived and well-rested individuals have shown that sleep-deprived individuals are more likely to be perceived as looking sad and/or having hanging eyelids, red and/or swollen eyes, wrinkles around the eyes, dark circles around the eyes, pale skin, and/or droopy corners of the mouth.24 Additionally, raters indicated that they perceived the sleep-deprived individuals as less attractive, less healthy, and more sleepy and were less inclined to socialize with them.25 Interestingly, attempts to objectively quantify the differences between the 2 groups have been less clear.26,27 Although the research is not yet definitive, it is feasible to assume that sleep deprivation is recognizable, and negative perceptions may be manifested about the sleep-deprived individual’s appearance. This can have substantial social implications given the perception that individuals who are viewed as more attractive also tend to be perceived as more competent.28 In the context of the military, this concept becomes highly relevant when promotions are considered. For some noncommissioned officer promotions in the US Army, the soldier will present in person before a board of superiors who will “determine their potential to serve at the recommended rank.” Army doctrine instructs the board members to “consider the Soldier’s overall personal appearance, bearing, self-confidence, oral expression and conversational skills, and attitude when determining each Soldier’s potential.”29 In this context, a sleep-deprived soldier would be at a very real disadvantage for a promotion based on their appearance, even if the other cognitive effects of sleep deprivation are not considered.