If you have ever slept on your arm and your leg, you might feel like a pins and needles sensation. Some people describe it as a fuzzy numbness, while for others it could be a prickling sensation. Medically, this term is known as paresthesia, which literally translates to "abnormal feeling". In many ways, it actually is the way we feel due to the changes in nerve function.So, what causes it?Before we get into that, let's identify how can you take a note of it:where you feel the sensationhow long does the sensation lastwhen it first startedwhether or not it is associated with certain positions or posturesPressureIf you notice that sensation is associated with specific position like sitting or crossing your legs, then it could be related to pressure. When you put pressure on certain areas of your body, it can lead to compression of both, a nerve and its blood supply. Therefore, it temporarily interferes with nerve's function and you experience paresthesia.MedicinesThere are certain medicines for conditions like HIV and cancer can affect nerve function and could lead to paresthesia. Certain supplements too can contribute to paresthesia. A bodybuilding supplement called beta-alanine is also known to cause pins and needles sensation.As per a 2012 study titled Mechanisms of Itch Evoked by β-Alanine showed that beta-alanine makes your nerves more sensitive, resulting in itching and tingling sensations. There are long-term supplementation of vitamin B6 can also cause you to feel the sensation, especially if you feel numbness in hands and feet.Other causesThere are other causes which are also related to such feeling:stroke or transient ischemic attackhead or limb traumavitamin B12 deficiencymultiple sclerosispanic attackdiabetesalcohol abusecarpal-, cubital-, or tarsal tunnel syndromesciaticathoracic outlet syndromesjogren’s syndromesystemic sclerosisvasculitisrheumatoid arthritislupusencephalitisLyme diseaseHIVheavy metal toxicitytumorIs it dangerous?This feeling is usually not dangerous, however, if there are underlying cause, it could be worrisome.Concerning symptoms may include:feverfatigueweaknessunintended weight lossnight sweatsbody acheschanges in vision, hearing, or speechchanges in appetite or thirstdizzinesslight-headednessanxietypain from a recent injury to the arearecent or current illnessWhat is the feeling like?The pins and needles feels like burning, pricking, itching, and crawling. The most common way people describe this as is "fallen asleep" of a certain body part. It starts as a tingling numbness and becomes a bit dull, and fuzzy feeling.What can be done when such happens all over your body?Usually, this sensation is rare in all over your body and it only affects a couple of your body parts. For instance, in vitamin B6-related paresthesia, you feel the sensation in your hands and feel but not in other body parts.However, if you do feel so, you can first try to reposition yourself, and do some stretches which will help you improve your blood circulation. If changing positions does not work, go see your healthcare professional and consult with them for any medication.