Just to report, I have the following problems with my fingernails:
Longitudinal ridges in all of my nails.
Some deep horizontal ones on my right hand middle finger(following 3 chest infections?)
The nails sometimes curl under at the ends, so I keep them short.
They are darker pink around the ‘half moons’ then pale, then darker again at the ends.
The half moons have disappeared on my little fingers, nearly so on ring fingers too.
They are brittle at times and split, sort of in layers, is the best explanation.
I get dark red or black flecks appearing in the nails from time to time.
They vary in strength, I suppose depending on my overall condition.