We further show that increased ICAM‐1 expression can be independently induced in an ex vivo scalp HF organ culture model through exposure to UA or fructose (which itself contributes to UA generation [20, 21]) and that the HF may locally produce fructose via the polyol pathway, suggesting an endogenous source for metabolic‐vascular stress in AA. Here, ICAM1 is linked to hydrops fetalis.