Rashes and Exanthems on Long Duration Space Flights

INTRODUCTION: As NASA expands its human space exploration to the Moon, Mars and beyond, it will be presented with many challenges, not the least of which will be dealing with medical conditions, which on earth are simple, but take on new levels of complexity in space habitats. Skin conditions exemplify this complexity. METHODS AND RESULTS: While skin conditions account for 7 % of outpatient presentations to a primary care provider in the United States, NASA Longitudinal Study of Astronaut Health (LSAH) database indicates that cutaneous manifestations are significantly prevalent on-orbit. Reviewing this data for US astronauts, there have been 90 total cases of skin rashes during 27.34 person-years of spaceflight, or 3.29 cases/person. Specifically, STS-1 though 114 had 56 cases, ISS Expeditions 1 though 13 had 7 cases, Mir had 4 cases, Skylab had 5 cases and the Apollo program had 18 cases. If there was a period of 24 hours or more between rashes in the same crewmember, this was counted as an additional case. DISCUSSION: This prevalence is likely due, in some part, to constraints of hygiene and to immunologic changes that occur. The stresses of microgravity and austere Earth environments such as the Antarctic, submarine and military deployments, no doubt, similarly contribute to cutaneous reactions; but the difference of the environments are significant enough to warrant further study and discussion. This paper will discuss rashes, exanthems, and cutaneous reactions in space habitats; it will address diagnosis, causation, mitigation and treatment of skin conditions seen on orbit, to date, with a look to anticipating what may be seen with larger crews on future extended duration expeditions.