The ill health of Henry IV

"The later years of Henry's reign were marked by serious health problems. He had a disfiguring skin disease, and more seriously suffered acute attacks of some grave illness in June 1405, April 1406, June 1408, during the winter of 1408–09, December 1412, and then finally a fatal bout in March 1413. Medical historians have long debated the nature of this affliction or afflictions. The skin disease might have been leprosy (which did not necessarily mean precisely the same thing in the 15th century as it does to modern medicine); perhaps psoriasis; perhaps a symptom of syphilis; or some other disease. The acute attacks have been given a wide range of explanations, from epilepsy to some form of cardiovascular disease." (from Wikipedia)

Scribal Terror adds this information from the English Historical Review of 1985:

The most detailed account [of Henry's "leprosy"] is that of Thomas Gascoigne in his Loci e Libro Veritatum. On 8 June 1405, Henry had ordered the beheading of Archbishop Richard Scrope of York after the latter's unsuccessful rebellion in alliance with the earl of Northumberland. At the moment of the execution, according to Gascoigne, the king was on his way from York to Ripon when he was suddenly stricken with "horrible leprosy of the worst sort." He was compelled to break his journey seven miles from York at the village of Green Hammerson, where he was tormented by a "horrible fear" in the night which made him waken his servants with shouts of "Traitors! Traitors! You have thrown fire over me!" His attendants soothed him with strong wine and on the following day he managed to reach Ripon, where he remained incapacitated for a week. An "eye-witness" told Gascoigne that on the eighth day after Scrope's execution, he saw "great leprous pustules" projecting like teats from the king's face and hands. (pp. 747-8)

I don't have an explanation to offer. This is also interesting:

It is said in Holinshed (and taken up in Shakespeare's play) that it was predicted to Henry he would die in Jerusalem. Henry took this to mean that he would die on crusade, but in fact it meant that, in 1413, he died in the Jerusalem Chamber in the house of the Abbot of Westminster.

There's another historical event similar to that - I'll try to find it.

Addendum. Found it -
Catherine de Medici had the Palace of the Tuileries built as a future residence for her in the parish of Saint Germain in Paris from 1564-1566. During its construction an astrologer told her that her death would occur in the vicinity of Saint Germain. She therefore kept away from the palace and the parish for the next 23 years. At the time of her death in Blois, she was given extreme unction by the Bishop of Clamercy, whose name was Jean de Saint Germain.