Carotenemia: This condition is caused by an excess of carotenoids in the blood, which can be due to a diet rich in carrots, sweet potatoes, or other carotenoid-containing foods. It leads to a yellowish discoloration of the skin, particularly on the hands and feet, without affecting bilirubin levels or causing anemia.

Niacin (Vitamin B3) overdose: High doses of niacin can cause skin flushing and yellowing due to the metabolite nicotinic acid, which can lead to carotenoid-like effects on skin color.
Lycopene excess: Similar to carotenemia, an excessive intake of lycopene (found in tomatoes) can cause a yellow-orange discoloration of the skin.
Topical or occupational exposure: Certain chemicals or dyes can cause localized yellow discoloration of the hands.

Hypothyroidism: Although less common, hypothyroidism can cause carotenemia due to decreased conversion of carotene to vitamin A. Missing this diagnosis could lead to untreated hypothyroidism.
Liver disease with normal bilirubin: Certain liver conditions, like primary biliary cirrhosis, can have normal bilirubin levels but still cause skin discoloration due to other metabolic byproducts.

Erythema palmare hereditarium (Tyrosinemia type II): A rare genetic disorder affecting amino acid metabolism, leading to skin lesions and possible yellowish discoloration.
Porphyrias: A group of disorders that can result in the accumulation of porphyrins, leading to various skin manifestations, including discoloration. However, these conditions are very rare and usually present with other significant symptoms.