I second shangrilada's asthma!Sam 'verse! I also have several Dean-centric fics bookmarked:
wave obscura has an excellent 'verse wherein Dean has Cystic Fibrosis: Because of Houdini (http://wave-obscura.livejournal.com/15876.html) and its sequel Because of the Amazons (http://wave-obscura.livejournal.com/44578.html)
Perfectly Functional Member of Society (http://spn-hurtcomfort.livejournal.com/5443.html?thread=211523#t211523) is a commentfic where Dean is diagnosed with narcolepsy. (Scroll down for the fic - there's also another fill closer to the top). S’okay. He’s My Brother (http://rainylemons.livejournal.com/17204.html) is a post-series fic where Dean has Chronic Fatigue Syndrome. The Damned Lie In Fire and In Snow (http://rainylemons.livejournal.com/41828.html) is primarily a case-fic, but Dean has Reynaud's in it.
Finally, several epileptic!Dean fics: Demon Blood, Sweat and Tears (http://ayslin.livejournal.com/28470.html) Fallen Idol (http://nong-pradu.livejournal.com/14619.html) Five Minute Warning (http://teashopmuses.livejournal.com/11539.html) Of Guilt and Bonding (http://neonchica.livejournal.com/8061.html)
no subject
wave obscura has an excellent 'verse wherein Dean has Cystic Fibrosis: Because of Houdini (http://wave-obscura.livejournal.com/15876.html) and its sequel Because of the Amazons (http://wave-obscura.livejournal.com/44578.html)
Perfectly Functional Member of Society (http://spn-hurtcomfort.livejournal.com/5443.html?thread=211523#t211523) is a commentfic where Dean is diagnosed with narcolepsy. (Scroll down for the fic - there's also another fill closer to the top).
S’okay. He’s My Brother (http://rainylemons.livejournal.com/17204.html) is a post-series fic where Dean has Chronic Fatigue Syndrome.
The Damned Lie In Fire and In Snow (http://rainylemons.livejournal.com/41828.html) is primarily a case-fic, but Dean has Reynaud's in it.
Finally, several epileptic!Dean fics:
Demon Blood, Sweat and Tears (http://ayslin.livejournal.com/28470.html)
Fallen Idol (http://nong-pradu.livejournal.com/14619.html)
Five Minute Warning (http://teashopmuses.livejournal.com/11539.html)
Of Guilt and Bonding (http://neonchica.livejournal.com/8061.html)