Hi, thanks for your query on HCM. There are several things that can cause a tingling, either a temporary tingling or long-term tingling (chronic). Some things that can cause temporary tingling include: -Longstanding nerve presses (such as sleeping, sitting cross-legged, etc.) -Frequency of rapid breathing -Panic attacks -Dehydration (less fluid) -Lack of blood supply in place of tingling While long-lasting tingling (chronic) can be caused by: -Brain disorders, spinal cord or peripheral nerves, including trauma, stroke, cerebral hemorrhage, tumor, infection of the brain and membranes, carpal tunnel syndrome, repetitive motion or long-term vibration etc. -Heart and blood vessel disorders -Metabolic and hormonal disorders: diabetes, low blood sugar, thyroid hormone disorders, menopause, calcium, potassium, sodium, abnormal urea. -Infection and post-infection syndrome -Connective tissue disorders and immunity -Blood, skin, bone and joint disorders -Lack of vitamins: vit B1, vit B5 and B12 -Malignancy / brain tumor Harmful or not, it is not known yet because further examination is necessary to determine the cause of your tingling. For a while, you can take a multivitamin B complex to reduce complaints. but you should consult a neurologist because your complaint is severe enough.