What are the risks associated with sclerotherapy in my arms ? what is the safest solution to use ?

Same as in the legs.: Although sclerotherapy can be done on any vein, the question is: why do it? Varicose veins of the arms do exist, but they are rare. If you just have prominent arm veins that are, otherwise, normal. I would encourage you to not sclerose them. You run the risk of getting a blood clot in your arm, having long lasting (or permanent) swelling, and of closing off other good veins. I wouldn't do it.

Ulcer: Ulcer and brwon spots are th commonest complication. Polidocanol appears to be safe but the choice of solution depends on the size of varicose veins.

DVT: Main risks are either deep venous thrombus or skin breakdown at the injection site.

Generally: Local complications: skin ulceration (concentration and volume dependent) and pigmentation of skin. Distant complication superficial and deep vein thrombosis with potential pulmonary emboli and even death. The gentlest solution is ethoxysclerol (asclera). Foamed solutions complications due to the minute air bubbles can cause TIA should a communication between the right and left heart exist.