It begins as a friend is telling you a story about spiders in her attic or a mosquito buzzes by near your ear. Before you know it, an invisible itch blossoms somewhere on your skin, compelling you to scratch. But why does simply thinking about bugs seem to conjure real, tangible sensations?

The phenomenon, sometimes called “contagious itching” or “phantom itch,” isn’t just in your imagination — it’s rooted in the powerful interplay between mind and body. The human brain is intrinsically sensitive to suggestion. When we hear about or imagine bugs crawling on skin, we begin to anticipate the feeling, which can lead to genuine physical sensations.

According to HuffPost Life, your brain can construct these feelings by activating the same neural circuits as if the experience was actually happening to you. Even hearing about or visualizing bugs crawling on you can trigger itching. It’s called a simulated somatosensory experience ─ meaning that the brain can generate these feelings internally, independent of direct stimulation.

If you’ve ever watched someone else scratch an itch and felt an urge to do the same, you’ve experienced contagious itching. Studies have shown that merely observing images or discussions of bugs, lice, or rashes can trigger itching in observers. The mind prepares the body for potential threats — even imagined ones — by activating the same neural pathways that process real itch.

Itching, or “pruritus,” is a complex sensory experience. In the skin, specialized nerve fibers called “pruriceptors” transmit itch signals to the spinal cord and brain. But itch can also originate from within the brain itself, without any peripheral trigger. This is known as “psychogenic itch” or “somatic itch,” where emotional or cognitive stimuli — such as anxiety, stress, or even suggestion — spark the sensation of itching.

From an evolutionary perspective, being hyperalert to the presence of bugs is advantageous. Parasites, such as fleas, lice, and mosquitoes, have long threatened human health by spreading disease and causing discomfort. Early detection of these pests was crucial for survival. Even today, your brain’s reaction to bugs can be protective. “Public health campaigns about lice or scabies outbreaks in schools may provoke discomfort, but that discomfort motivates inspection and early treatment, good for containment,” explains Dr. Shaheen Lakhan, a board-certified neurologist.

For most people, the imaginary itch fades once the conversation or story moves on. However, for some, especially those with anxiety, obsessive-compulsive tendencies, or a history of skin conditions, psychogenic itch can become chronic. Persistent thoughts, stress, or exposure to bug-related stimuli may trigger ongoing itching and scratching, says Lakhan, leading to skin lesions from scratching, heightened anxiety and sleep disturbance.

If you find yourself scratching at the mere mention of bugs, you’re not alone — and there are ways to break the cycle.

• Recognize that the sensation is coming from your brain, not your body, says Lakhan. Practice mindfulness. Focus on your breathing or surroundings to redirect attention away from imagined sensations.

• Keep your hands busy. “Do something tactile, like running your hands under cold water or grabbing a stress ball or beaded bracelet,” he advises. This gives your brain a new signal to process.

• Limit exposure. If certain images or stories reliably make you itchy, consider limiting your exposure, especially during periods of stress.

• Use moisturizers. Dry skin can worsen itch, so keeping skin hydrated may reduce overall sensitivity.

On the other hand, you can also try to expose yourself to more bugs and itchy creatures, suggests other experts. “Your reaction level may go down, since your body kind of learns to relax in the presence of bugs,” suggests neuroscientist Friederike Fabritius.