There is some speculation that Poe had a brain tumor that had gone untreated for many years. Wasn't much they could do in the 1830s. He bled from the ear on occasion and went temporarily mad at least twice so there was a problem. Alcohol became a major problem after the death of Virginia Clemm in 1847. It did cost him his job at the Southern Literary Messenger in 1835 but Thomas White hired him back on the promise that he would never show up for or miss work for being drunk. Poe kept his word and resigned from the Messenger a couple of years later on good terms with White whose magazine published some of Poe's material in the 1840s. Several years passed with Poe touching no alcohol.

Poe did try to commit suicide with laudanum--tincture of opium--but was so unfamiliar with its use that the dose wasn't nearly enough. That was over the death of Virginia as well. Griswold used this incident to make Poe into an opium addict which he was not. The most famous photograph of Poe was taken shortly after that incident where he looks pale, tired, bags under the eyes, etc. It's not how he normally looked but it seemed to fit so many of the narrators of his horror stories that it became his most famous portrait. The mustache, by the way, was only something Poe wore the last year of his life. He was clean-shaven most of his life.

Poe married Sarah Elmira Royster whom he was once engaged to in his university days but they drifted apart. When they met again, they realized they were still in love. Poe saw her on September 26, 1849 and departed for Baltimore by steamer the following day. She said he had a high fever and said he didn't feel well but said he was still going to Baltimore over her objections. He stopped at a Dr. Carter's office but took the doctor's cane with him by accident. That worried Elmira a great deal as Poe was very attentive about stuff like that. So we know he wasn't well when he left for Baltimore.

He arrived on a Sunday the 29th and was not seen or heard from until Thursday, I believe, on October 3. His old friend Dr. Snodgrass got a letter from someone claiming he found Poe at the polls nearly unconscious and spoke with him and Poe mentioned Dr. Snodgrass. The letter said to come quickly as Poe was in great distress and need. Snodgrass hurried and found Poe unconscious and had him hospitalized. Poe could not speak and nothing could be gotten from him about how he ended up in his condition.

Oddly, Poe was wearing shabby clothes not his own. He arrived in Baltimore with $300 from a successful lecture but that too was gone. The doctor at the hospital, John Moran, examined Poe and said he had not been drinking but otherwise did not know what was wrong with him. On Saturday, Poe began hallucinating and called out for "Reynolds." No one knows who this was but some think it was writer Jeremiah Reynolds whose lobbying Congress to finance Antarctic expeditions to find the South Polar opening inspired Poe to write "Arthur Gordon Pym of Nantucket". Others think it was G.W.M. Reynolds who was literary editor of Snowden's Ladies Companion when the magazine published Poe's "Murder of Marie Roget" in three installments.

About 3 o'clock in the morning, Poe awoke from his delirium and muttered his final words: "Lord help my poor soul" and was pronounced dead at age 40 of "brain congestion" whatever that is. His final words were a line from a prayer taught to him by the Sons of Intemperance--a forerunner of Alcoholics Anonymous. Poe had joined them to do something about his drinking because he kept relapsing.

As for his change of clothes, I think he ran into a coop gang. Political parties often sent out gangs to abduct people and force them to vote for the same candidate at various polling places--stuffing the ballot box, basically. Often, they would dress the person in various changes of clothing and send them back through the same places to vote again. They did this usually by drugging the person or getting him drunk. Sometimes a beating was necessary but Poe's already delirious state they probably didn't need to do anything to him. But evidently, he collapsed on them and no further use could be gotten from them so they took his money and clothes and left him. The fact that Poe was found at a polling place would substantiate this.

That's about all we know concerning his death.