Some 20 years ago, I picked up a little treasure at our medical school library's book sale: Von Hebra on: Diseases of the Skin (1867). While it is of little other than historical value at present, I thought it might be entertaining to take a look at the chapter on psoriasis.
Von Hebra was the head of what is ostensibly considered the first "official" department of dermatology at the University of Vienna. More than any other modern dermatologist, he is responsible for naming and categorizing the dermatology lexicon still in use today.
By researching literature of the ancient Greeks, Egyptians and medieval scholars, he separated out the many diseases confused and lumped together with psoriasis into their proper categories. The disease he describes and categorized as psoriasis is in fact the disease we consider as psoriasis today.
Many people wonder why psoriasis has such a strange sounding name, but it's certainly much less of a tongue twister than Dartre squameuse centrifuge of Alibert another name for this disease laid to rest by the esteemed professor (thank you Dr. Von Hebra).
Among the causes of psoriasis Von Hebra lists climatic conditions, habits (including brandy) and nervous temperaments. Not too far off the mark from what we understand today (genetics was not yet considered). He claims to have treated more than 1,000 patients with psoriasis and found that, in general, they were overall healthy and free from other significant illness, and that no particular occupation predisposed people to the condition. These findings were somewhat divergent from his contemporaries of the day.
Treatment-wise, Von Hebra was not very happy with the various medications of the day which he claimed tended to cause "violent reactions." Instead he preferred to use arsenicals (medications derived from arsenic). Although these medicines did work and were employed for a variety of ailments, they are obviously much too toxic to be considered as a medical treatment for any disease today. Tar preparations were also a part of his treatment armamentarium. It makes you wonder: What will doctors 100 years from now say about our current treatments?
That concludes this brief look at psoriasis from a historical perspective. From a practical point of view, the most important thing to glean from Von Hebra might be to look at treatments with a somewhat cynical view -- to not just accept historical or anecdotal evidence as a means of establishing whether or not a treatment is useful, but to use scientific observation and testing instead.