My doctor listened to my story. Then she asked a few questions:
- Did the sensation happen when you were falling asleep or waking up?
- Do you have a history of anxiety?
- Are you under a lot of stress right now?
- Have you changed any medications recently? (No.)
- Do you have any other symptoms? (I was tired — but that was from not sleeping.)
She nodded and said, « I don’t think you have bugs. I think you’re experiencing something called formication. »
I’d never heard the word.
Formication (for-mih-KAY-shun) is the medical term for the sensation of insects crawling on or under your skin when nothing is actually there. The word comes from the Latin formica, meaning « ant. » It’s a type of tactile hallucination — a false perception of touch.
What causes it:
- Stress and anxiety (most common — that was my cause)
- Sleep deprivation (which I now had in spades)
- Hormonal changes (perimenopause, menopause, pregnancy)
- Medication side effects (certain antidepressants, stimulants, blood pressure meds)
- Alcohol or drug withdrawal
- Skin conditions (dry skin, eczema, neuropathy)
- Nutritional deficiencies (low iron, B12, or folate)
- Neurological conditions (Parkinson’s, multiple sclerosis, shingles)
In my case, the answer was simple: stress and lack of sleep. I was in a high-pressure period at work, sleeping poorly, and my brain was essentially glitching, creating sensations that weren’t real.
Why Your Brain Creates Phantom Crawling Sensations
Let me explain the science.
Your brain receives constant sensory input from your skin — touch, pressure, temperature, pain, vibration, and the sensation of movement (like a hair brushing against your arm). Usually, it filters out irrelevant sensations (the feel of your clothes, the pressure of the mattress, the air on your skin) and alerts you to important ones (a bug, a sharp object, a hot surface).
When you’re stressed, tired, or anxious, your brain’s filtering system becomes less efficient. It may misinterpret normal sensations (the brush of a bedsheet, a muscle twitch, a hair falling) as something more alarming — like a bug crawling.
This is the same mechanism behind « phantom vibrations » (feeling your phone buzz in your pocket when it didn’t). Your brain is primed to expect a sensation, and it creates one.
The more you focus on the sensation, the worse it gets. The worse it gets, the more you stress. The more you stress, the worse your sleep. It becomes a vicious cycle.
Other Common Causes of Nighttime Crawling Sensations
See more on the next page
