Long COVID symptoms: A mysterious illness that may affect up to 80% of COVID cases

Long Covid is, quite possibly, the great enigma of our time.

Exactly what it is, when it appears, how long it lingers, how many patients it affects (from 10% to 80% of COVID survivors, depending on the study), and what just causes it—beyond the seemingly obvious—are debated, with new hypotheses floated daily.

As research into the vexing new disease expands, it seems that almost anything and everything could be a symptom—from ear numbness, a sensation of “brain on fire,” and erectile dysfunction to irregular menstrual periods, constipation, and peeling skin.

For those investigating the mysterious malady, that’s a real problem.

Recently scientists have attempted to categorize Long COVID patients into subgroups, hypothesizing that the condition that could affect up to 23 million Americans, according to federal officials, isn’t one thing, but many.

A picture is beginning to emerge of “groups of symptoms that have yet to be characterized well enough to call one or several diseases,” Justin Reese, a computational biologist with Berkeley Lab—a multi-science lab supported by the U.S. Department of Energy—told Fortune this week via email.

A study released last month used artificial intelligence to classify tens of thousands of U.S. “long haul” patients using their electronic health records. The main symptom sets his study found include patients who primarily suffer from:

Blood and circulatory system issues like heart failure, arrhythmias, and chest pain.

Respiratory system issues like throat and chest pain, upper respiratory infections, asthma, and lower respiratory disease.

Musculoskeletal and nervous system issues like connective tissue disorders, osteoarthritis, and musculoskeletal pain.

Digestive system issues like abdominal and pelvic pain, nausea, vomiting, and disorders of the urinary system.

But theories abound. Dr. Alexandra Brugler Yonts, an infectious disease specialist at Children’s National Hospital in Washington, D.C., recently shared her list of possible buckets with Fortune. They include patients who:

Have sustained long-term organ injury from COVID, such as lung damage.

Are suffering from inflammation resulting from COVID.

Have developed dysautonomia, which leads to changes in blood pressure and heart rate upon changes in position, like sitting or standing.

Have ongoing COVID viral activity.

Have immune systems that over-corrected in response to COVID and now under-respond to pathogens.

Categories may extend well beyond a handful, however, as symptoms have been identified in 10 of the 11 organ systems, according to a landmark study published in British medical journal The Lancet in July.

Here are 100 of the most common symptoms the study identified, by category:

Emotion and mood

Anxiety

Irritability

Depression

Tearfulness

Apathy

Sense of doom

Depersonalization

Anger

Impulsivity

Suicidality

Euphoria

Delusions

Sensorimotor

Dizziness

Pins and needles feeling

Tremors

Numbness

Noise sensitivity

Ringing in the ears

Feeling of brain pressure

Nerve pain

Sensation of brain "on fire"

Inability to yawn

Sleep

Insomnia

Awakened by feeling of inability to breathe

Vivid dreams

Nightmares

Restless leg syndrome

Sleep apnea

Cognitive functioning

Brain fog

Poor attention span

Difficulty thinking

Sudden confusion

Racing thoughts

Memory

Short-term memory loss

Long-term memory loss

Forgetting how to do routine tasks

Inability to make new memories

Headaches

Behind the eyes

All over

Temples only

Base of skull

After mental exhaustion

Migraines

Taste and smell

Loss of taste

Loss of smell

Altered taste

Altered smell

Heightened taste

Heightened smell

Phantom smells

Phantom taste

Speech and language

Difficulty finding the right words

Difficulty reading

Difficulty understanding speech

Difficulty speaking

Difficulty writing

Slurred speech

Speaking unrecognizable words

Hallucinations

Visual

Auditory

Tactile

Systemic

Chills, sweats

Elevated temperature

Fatigue

Low temperature

Pulmonary, respiratory

Breathing difficulties but normal oxygen saturation

Cough with mucus

Coughing up blood

Dry cough

Sinus issues

Rattling of breath

Shortness of breathe

Sneezing

Reproductive, genitourinary, endocrine

Menstrual issues

Bladder control issues

Cardiovascular

Fainting

Heart palpitations

Burning in the chest

Bulging veins

Dermatologic

"COVID toe"

Peeling skin

Rashes

Gastrointestinal

Abdominal pain

Constipation

Diarrhea

Loss of appetite

Reflux

Nausea

Vomiting

Immunological, autoimmune

New allergies

New anaphylaxis reactions

Musculoskeletal

Bone aches

Joint pain

Muscle aches

Muscle spasms

Chest tightness

Head, ear, eye, nose, throat

Hearing loss

Runny nose

Sore throat

Vision symptoms

Source: Fortune

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