Hypovolemia: Mottling skin can be a sign of decreased peripheral perfusion, which can occur in hypovolemic states due to decreased blood volume. This can happen without significant hemodynamic stenosis on arterial exam, as the issue is more related to volume status than to fixed arterial obstruction.

Sepsis: Early stages of sepsis can present with mottled skin due to peripheral vasodilation and decreased perfusion, even before hemodynamic instability becomes apparent.
Anemia: Severe anemia can lead to decreased oxygen delivery to tissues, resulting in mottling, without necessarily causing hemodynamic stenosis on arterial exam.
Hypothyroidism: This condition can cause changes in skin perfusion and temperature regulation, leading to mottling.

Aortic Dissection: Although less likely, aortic dissection can cause differential perfusion to limbs, potentially leading to mottling without significant stenosis on a standard arterial exam. It's crucial to consider this diagnosis due to its high mortality rate if missed.
Vasculitis: Certain types of vasculitis can affect small vessels and cause skin mottling without significant large vessel stenosis on exam.

Ehlers-Danlos Syndrome: This genetic disorder can affect blood vessels and lead to abnormalities in skin perfusion, potentially causing mottling.
Buerger's Disease (Thromboangiitis Obliterans): A rare disease of the small and medium-sized arteries and veins, which can cause skin mottling among other symptoms, typically in young smokers.
Complex Regional Pain Syndrome (CRPS): Can cause changes in skin temperature and perfusion, leading to mottling, usually after an injury or trauma.