As much as I like Michael Fumento, I have to point out that this statement is erroneous. The skin disease, chloracne, as well as other toxic effects, is brought about by ingestion of large quantities of dioxin (2,3,7,8-TCDD). TCDD's toxic effects are mediated through a single receptor, which interacts with nuclear DNA and causes up and down regulation of the expression of several genes. It is the inappropriate regulation of these genes that (eventually) leads to the symptoms of TCDD toxicity, including chloracne.
If a large enough dose of TCDD could be absorbed through the skin, it would cause the same symptoms as ingested TCDD--the effect is systemic, not topical.
(I earned my Ph.D. by researching how TCDD affects gene regulation.)
Sounds like what I kept saying.