Can poison ivy poisoning spread internally?

No: Only if you get it in your mouth.

No: The reaction poison ivy "rhus" antigen affects only the skin structures that it comes in direct contact with;either primarily with plant contact or secondarily thru a scratch from contaminated fingers or clothing. The weeping material from leasons do not spred the problem. A good soapy wash after exposure limits breakouts by removing the stimulous. I'm not aware of the effect if you eat it.

No: However, it is possible to have an "id reaction" or autoeczematization. This represents a generalized acute skin reaction and can occur from a variety of stimuli, including infectious, contact allergens, and inflammatory skin conditions.

Yes -- if vaporized: If poison ivy is burned, the oils vaporize, and you breathe it in -- yes, you can have internal poison ivy reactions which could be very dangerous. Sometimes this can happen accidentally, like when clearing a yard in winter, that you don't realize has poison ivy vines on trees, etc. (i've seen it happen.) poison ivy just on your skin will not "spread" internally, though.