Comment to: Significant endothelin release in patients treated with foam sclerotherapy, by Frullini A, Barsotti MC, Santoni T, Duranti E, Burchielli S, Di Stefano R. Dermatol Surg 2012;38:741–7.

A greater incidence of cough, transient visual and neurological disturbances have been reported with foam rather than with liquid sclerosant. These complications have often been associated with migraine and patent foramen ovale (PFO), a common condition affecting approximately 25% of the whole adult population. Foam bubbles may pass through a PFO to the left heart chambers, with consequent paradoxical systemic embolization. Visual and neurological disturbances have often been reported also with liquid sclerosants which conflicts with the bubble theory