Dry gangrene or arterial insufficiency: Given the patient's history of smoking and the presentation of peeling skin on bilateral feet, this diagnosis is likely due to reduced blood flow to the extremities.

Chronic venous insufficiency: Although the patient has no history of DVT and a normal ABI, chronic venous insufficiency could still cause skin changes and peeling due to poor circulation.
Diabetic foot: If the patient has undiagnosed or unmanaged diabetes, this could lead to peripheral neuropathy and poor wound healing, resulting in peeling skin.
Eczema or contact dermatitis: Skin conditions like eczema or contact dermatitis could cause peeling skin on the feet, especially in the elderly.

Carbon monoxide poisoning: Although unlikely, carbon monoxide poisoning can cause cherry-red discoloration of the skin, which may be mistaken for peeling skin.
Sepsis: If the peeling skin is a sign of an underlying infection, sepsis is a potentially life-threatening condition that should not be missed.
Vasculitis: Certain types of vasculitis, such as Buerger's disease, can cause skin lesions and peeling due to inflammation of the blood vessels.

Pellagra: A rare condition caused by niacin deficiency, which can lead to skin changes, including peeling.
Kawasaki disease: A rare condition that can cause skin peeling, although it is more commonly seen in children.
Erythromelalgia: A rare disorder that causes burning pain, heat, and redness in the hands and feet, which may be accompanied by peeling skin.