Anhidrosis and itchiness


Two of my Hanoverian mares who have Cushings developed Anhidrosis suddenly this Summer in mid July. They had never displayed this problem before.  Suggestions besides keeping them in under fans during the heat of the day.  Also one of the mares has had itchiness which she has had for over a year now.  It doesn't seem to be a normal seasonal allergy or sweet itch.  I know Cushings can cause the skin to be dry but have her on Coolstance which is a safe way to give her Omega for skin in her diet. My Veterinarian suggested Zyrtec or Ceritizine , 10 tablets twice a day.  I was wondering if this was the best way to treat and can she stay on this antihistamine year round as the itchiness was occurring last year in the Winter.  I do a trace clip on all 3 of my mares to help with sweating when working them in the Winter.  I do blanket at night when in their stalls and put sheets when turning them out during the day if it is colder than 40 degrees.  Thanks
Trudy Adams SC 2019


Hi Trudy,
I don’t see any recent bloodwork in your case history files.  From what I can tell, your mare, Ani, was tested positive for PPID in fall of 2019.  You began treating her with 1 mg of pergolide but have not tested since. So, you don’t really know if 1 mg of pergolide was enough to manage her PPID at that point, nor do you know if you’re giving enough pergolide to treat this progressive disease several years later.
Anhydrosis often comes with PPID but I don’t think that it always goes away with adequate PPID treatment.  The itchiness, though, might well disappear with more pergolide.
Martha in Vermont
ECIR Group Primary Response
July 2012 
Logo (dec. 7/20/19), Tobit(EC) and Pumpkin, Handy and Silver (EC/IR)

Martha and Logo


Sherry Morse

I'd suggest checking ACTH levels of both mares as they may not be controlled on the current dose of Prascend. We also do not usually recommend Coolstance for IR horses -  You might see better results with flax if you're looking to get the proper Omega ratio. 

Eleanor Kellon, VMD

You can safely give antihistamines but making sure ACTH is controlled may be more productive. Also have her checked carefully for lice. They're easy to miss.

Coolstance is the worst possible oil for omegas, having virtually none. It's borderline safe on carbs, too high in fat and has an unfavorable amino acid profile. Go to flax.
Eleanor in PA 
EC Owner 2001