Invisible illness

An invisible illness or invisible chronic illness (ICI) or hidden illness is defined as any illness that it is noticeable or evident to others (Vickers, 1998).

Examples
Invisible illnesses may be physical or psychological illnesses, for example: Some invisible illnesses are well understood by medical professionals and have clear medical tests and treatments, for example diabetes, but others are poorly understood or "medically unexplained" and often go undiagnosed or misdiagnosed, for example ME/CFS, fibromyalgia.
 * Arthritis
 * Cancer
 * Chronic pain
 * Depression
 * Endometriosis
 * Fibromyalgia
 * HIV/AIDS
 * Inflammatory bowel disease
 * Irritable bowel syndrome
 * Lupus
 * Lyme disease
 * ME/CFS
 * Post-polio syndrome
 * Migraine
 * Multiple sclerosis, which can be either visible or invisible
 * Thyroid illnesses

But you don't look sick!
In both society and the disability / social security systems, people are considered "healthy until proven sick" (Stone, 1984).

Passing for "normal"
People with invisible illnesses are usually able to choose whether to disclose or hide their illness or aspects of their illness, and may attempt to "pass for normal".

Stigma and discrimination
The lack of visibility of an invisible illness may avoid some types of stigma and discrimination but others, for example a lack of social support from family or friends, and difficulty accessing disability supports.

Many invisible illnesses are chronic illness, meaning that they are long term health conditions and do not have a known cure.

Signs and symptoms
Invisible illnesses can have many different signs and symptoms, but people usually don't look "visibly ill", for example they generally do not present with obvious signs of mobility problems such as poor coordination or leg braces, and they don't have obvious skin or facial changes such as yellowed skin, extreme pallor, swelling or excessive bruising.

Effects
The effects of having a chronic illness that is invisible include: Some invisible illnesses do not have a particular diagnostic test or are relatively rare, which can mean that some doctors doubt patients, leading to them neglecting the patient's basic medically needs. An invisible illness is not necessarily a mild or non-serious illness, for example when HIV/AIDS first emerged it caused many deaths and had few visible signs until the disease was in the later stages.
 * Difficulty finding appropriate medical care
 * Difficulty getting diagnosed, and difficulty describing symptoms
 * Symptoms may be inappropriately blamed on stress, known as psychologization
 * Inappropriate psychosomatic treatment approaches can cause harm
 * Lack of support from friends and family
 * Suspicion and withdrawal from others
 * Confusion, loneliness, feelings of self-pity and self-doubt
 * Denial of support from the healthcare and disability systems, causing avoidable physical and financial harm

Treatment
Treatment usually depends on the illness diagnosed, but if there is no clear diagnosis then treatment can be aimed at particular symptoms.

ME/CFS
ME/CFS is often given as an example of an invisible illness, but when severe or very severe patients may look visibly ill, for example as a result of using a wheelchair, visible muscle wasting, or needing a feeding tube.

News and articles

 * 2020, Chronic fatigue syndrome: Living with an invisible illness - BBC News
 * 2020, How To Talk To Your Doctor If You're Experiencing Chronic Pain - Huffington Post
 * Patient Voices: Fibromyalgia - New York Times
 * 2000, What Happens When You're Disabled but Nobody Can Tell - New York Times
 * 2009, Hidden disorder 'stripped me of life'

Notable books and articles

 * 2000, Sick and Tired of Feeling Sick and Tired. Living with Invisible Chronic Illness - Donoghue and Siegel (Book)
 * 2011, Invisible chronic illness inside apparently healthy bodies (Full text)
 * 2012, Sick and Tired of Feeling Sick and Tired. Living with Invisible Chronic Illness -(Article, Full text)
 * 2014, Invisible Illness: Coping with misunderstood conditions - Megan A. Arroll
 * 2020, A relational analysis of an invisible illness: A meta-ethnography of people with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and their support needs (Full text)