The uncomfortable sensation of feeling something sharp embedded beneath the skin, often described as having “fiberglass in the skin,” is a common complaint. This feeling of pricking, tingling, or crawling on or under the skin is medically known as paresthesia, which refers to an abnormal sensation. When this sensation involves crawling or biting without a physical cause, it is called formication, a term derived from the Latin word for ant. This feeling can stem from a direct external irritant or signal that the body’s nervous system is misfiring, requiring investigation to determine the underlying cause.
Actual Fiberglass Exposure and Immediate Care
Fiberglass is a material composed of extremely fine glass fibers used widely in insulation, construction, and plastic reinforcement. The irritation it causes is mechanical irritant contact dermatitis, occurring when these fibers penetrate the outer layer of the skin. Symptoms include intense itching, a burning sensation, and a visible rash of small, red bumps where the fibers have lodged.
If exposure occurs, the immediate goal is to remove the fibers without pushing them deeper. Do not scratch or rub the affected area, as this can embed the glass spicules further. Remove contaminated clothing and immediately take a shower, using cool or lukewarm water rather than hot water.
Cool water helps keep the skin’s pores closed, preventing the fibers from migrating deeper. Use mild soap and gently wash the area with a soft cloth to sweep the fibers away from the surface. Applying tape, such as duct tape or packaging tape, to the affected area and quickly peeling it off can also help lift out the embedded fragments.
Neurological Conditions That Cause Prickling Sensations
When the sensation of prickling or crawling is not caused by an external irritant, the source often lies within the nervous system. This paresthesia signals that sensory nerves are damaged or irritated, causing them to send abnormal signals to the brain. The brain misinterprets these signals as a physical sensation like “pins and needles” or the feeling of something sharp under the skin.
This condition is frequently symptomatic of peripheral neuropathy, which is damage to the nerves outside of the brain and spinal cord. Diabetes is a common systemic cause, as high blood sugar levels can damage the blood vessels supplying the nerves. This nerve damage often begins in the longest nerves first, leading to prickling sensations in the feet and hands.
Other systemic conditions leading to peripheral neuropathy include thyroid disorders, such as hypothyroidism, and autoimmune diseases like Lupus or Multiple Sclerosis. Vitamin B12 deficiency is also a recognized cause, as this vitamin is necessary for nerve health and the proper formation of the myelin sheath. Localized nerve compression, such as carpal tunnel syndrome in the wrist, is another significant cause.
Skin and Environmental Factors That Mimic Fiberglass
Beyond systemic nerve issues, localized skin and environmental factors can produce a sensation mimicking physical irritants. Severe skin dryness (xerosis) causes generalized itching and prickling, especially during colder months or in low-humidity environments. When the skin lacks moisture, the outer barrier becomes compromised, leading to inflammation and hypersensitivity.
This barrier dysfunction can cause sensory nerve endings to become overly reactive, leading to sensations of stinging or burning even from contact with clothing or water. Contact dermatitis, either irritant or allergic, results from the skin reacting to substances like harsh detergents, soaps, or cosmetic ingredients. The resulting inflammation triggers nerve signals that the brain perceives as a sharp or prickly sensation.
In some cases, the persistent feeling of crawling can be a tactile hallucination, a misperception that originates entirely within the brain. This is a symptom seen in conditions such as Delusional Parasitosis, where the person maintains a false belief that they are infested with parasites or tiny fibers. Certain medication side effects or substance withdrawal can also temporarily trigger this neurological misinterpretation.
When to Seek Professional Diagnosis
If the prickling or crawling sensation persists for more than a few days after removing environmental irritants, or if the cause is unknown, a medical consultation is necessary. Persistent paresthesia may be the first warning sign of an underlying medical condition requiring treatment. A healthcare professional, such as a primary care physician, dermatologist, or neurologist, can determine the source of the symptoms.
It is important to seek prompt medical attention if the sensation is accompanied by other neurological symptoms, including muscle weakness, sudden loss of coordination, or numbness affecting one side of the body. These symptoms may indicate a more serious condition affecting the central nervous system. Diagnostic steps often involve blood tests to check for systemic causes like diabetes or vitamin deficiencies, and nerve conduction studies to evaluate nerve function.