Compassion fatigue is an evolving concept in the field of traumatology. The term has been used interchangeably with secondary traumatic stress (STS), which is sometimes simply described as the negative cost of caring. Secondary traumatic stress is the term commonly employed in academic literature, although recent assessments have identified certain distinctions between compassion fatigue and secondary traumatic stress (STS).

Compassion fatigue is a form of traumatic stress resulting from repeated exposure to traumatized individuals or aversive details of traumatic events while working in a helping or protecting profession. This indirect form of trauma exposure differs from experiencing trauma oneself.

Compassion fatigue is considered to be the result of working directly with victims of disasters, trauma, or illness, especially in the health care industry. Individuals working in other helping professions are also at risk for experiencing compassion fatigue. These include doctors, caregivers, child protection workers, veterinarians, clergy, teachers, social workers, palliative care workers, journalists, police officers, firefighters, paramedics, animal welfare workers, health unit coordinators, and student affairs professionals. Non-professionals, such as family members and other informal caregivers of people who have a chronic illness, may also experience compassion fatigue. The term was first coined in 1992 by Carla Joinson to describe the negative impact hospital nurses were experiencing as a result of their repeated, daily exposure to patient emergencies.

People who experience compassion fatigue may exhibit a variety of symptoms including, but not limited to, lowered concentration, numbness or feelings of helplessness, irritability, lack of self-satisfaction, withdrawal, aches and pains, exhaustion, anger, or a reduced ability to feel empathy. Those affected may experience an increase in negative coping behaviors such as alcohol and drug usage. Professionals who work in trauma-exposed roles may begin requesting more time off and consider leaving their profession.

Significant symptom overlap exists between compassion fatigue and other manifestations, such as posttraumatic stress disorder (PTSD). One distinguishing factor lies in the origin of these conditions, with PTSD stemming from primary or direct trauma, while compassion fatigue arises from secondary or indirect trauma.

Compassion fatigue has been studied by the field of traumatology, with Charles Figley playing a pivotal role by characterizing it as the "cost of caring" experienced by individuals in helping professions. The term was introduced to the literature in 1992 by Carla Joinson to describe the negative impact hospital nurses were experiencing as a result of their repeated, daily exposure to patient emergencies. However, the phrase had been in use as early as 1961, and was popularized in 1985 when Bob Geldof cited it as his reasoning for ending his charity work after Live Aid.

To a certain extent, the term "compassion fatigue" is considered somewhat euphemistic and is used as a substitute for its academic counterpart, secondary traumatic stress.

Compassion fatigue has also been called secondary victimization, secondary traumatic stress, vicarious traumatization, and secondary survivor. Other related conditions are rape-related family crisis and "proximity" effects on female partners of war veterans.