Is it possible that sclerotherapy have triggered a varicose vein?

Possible...: When varicose veins are treated with sclerotherapy, it is possible, but not common, that blood flow may be redistributed from the now closed varicosities to nearby vein tributaries which may gradually enlarge and become varicose with time. Sclerotherapy of spider veins will not result in the development of varicose veins, however.

Appearances: Treating varicose veins, especially larger ones, can sometimes cause less noticeable vein branches to become more apparent. In this case, it wasn't a normal vein that was made abnormal by the treatment, it was a vein that was already abnormal and needed to be treated anyway. Vein treatment is always a process and it is common for more than one treatment is required to treat everything.

Possible: Varicose veins is a progressive chronic disease. Most patients will develop new abnormal segments with time. If a segment has borderline function and treatment of other segments increases its flow burden, it may become varicose. These are usually easily treated.

Seems unlikely.: I have never seen the treatment of spider veins lead to the formation of varicose veins. I have seen new spiders form (neovascularization) after spider vein injections. If varicose veins form after spider vein treatment, i would be suspicious that there is underlying saphenous valve insufficiency(reflux). You should have a venous evaluation by a vein specials.

Unusual: This could be unusual but possible. With varicose vein treatment, after the abnormal vein is closed with sclerotherapy the blood that was in that vein will reroute to adjacent veins. If those adjacent veins are abnormal they may present as a new varicose vein. This rarely occurs. Can sometimes also get "matting" complication where small thread or spider veins form but usually resolves with time.

Sclerotherapy: infrequently treatment with sclerotherapy can lead to matting, which means new vein development of the same size around the area of treatment as result of inflammatory process. It is highly unlikely that a large varicose vein will develop as the result of sclerotherapy