marked by a small stain on the throat.
marked by a murky blotch on the throat.
marked by a dark mark on the throat.
marked by a jagged scar on the throat.
marked by a black miasma on the throat.

There are a total of fifteen levels, the black miasma is the highest (level 15).
If you have no mark, or a mark too weak to be cleansed (level 1):
You snap your fingers and warm water showers down upon yourself, and you scrub under your armpits until you are squeaky clean.

Otherwise:
You snap your fingers and warm water showers down upon yourself, and you scrub all over, trying to wipe away the dark mark that stains your skin.

-update wiki-

Super! Thanks.

In a log I have this diagnose line "ravaged by an imbalanced homeostasis." for some plague thing a Moondancer gave me. I don't know what the affliction is and I don't see it in the web pages.

That's aurawarp (Healing skillset).

No that's plague which prevents some forms of curing. Aurawarp gives plague periodically.

This line (when you diagnose):
suffering under a warped aura of infirmity.

is for Aurawarp.

Viynain, here are afflictions from the Lore Wiki that weren't in my list so they weren't in your list back when I went over it. I didn't check to see if you have added any of these since.

absinthe
antlers
bad trip
blues
bubble
bumblebee
burning censer
burnout
crocodile
crucified
dead reckoning
death
dolphin
dragon
fleshtone
glacier
gunk
haunted
homeostasis
illusory wounds
infiltration
kneeling
lapsing consciousness
lion
maggoting
manaleech
muted
papaxi
permasleep
shattered ego
shrubbing
skull
sleeping
spider
stars
stun
tripping
twin crystals
unconscious
volcano

EDIT: had left volcano off the list

Some of those are in Viynain's list but just not broken out the same way. For instance, the twelve astrology spheres are in his list as a single "Astrospheres" item. Homeostasis is a part of AuraWarp, I separated it out because it has a separate DIAG line. Etc.