Devon Rex care: greasy skin, blood type B and staying warm

The Devon Rex coat is a mutation, and most of the breed's care follows from it. The curl comes from a change in the keratin 71 (KRT71) gene, and every Devon Rex tested in that study carried two copies. The result is a short, wavy coat with few guard hairs and some bare or thin patches. Alongside it come skin that turns greasy more easily than in other cats and a cat that looks for warm places. The breed also carries an inherited muscle disorder and a high share of blood type B, both of which an owner should know about before a vet ever needs to.

Feeding a small, thin-coated cat

The Cat Fanciers' Association gives typical adult weights of six to nine pounds (about 2.7 to 4 kg), with males somewhat larger. For a cat of that size the Merck Veterinary Manual formula is a reasonable starting point. Resting energy requirement (RER) is 70 multiplied by body weight in kilograms raised to the power 0.75. Neutered adults get about 1.2 times RER, intact adults 1.4 times and kittens 2.5 times. Rounded to the nearest 5 kcal:

Merck notes that two animals of the same weight can differ by as much as 30% in what they need, and that the calculation assumes a thermoneutral environment. A cat with little coat living in a cool house may sit outside that range and burn extra energy keeping warm. We found no study that measures how much more this breed needs, so any increase should be adjusted by body condition, not by a fixed percentage.

In practice:

• Feed a complete and balanced food for the cat's life stage, wet, dry or both.
• Weigh portions and split the day's food into two to four meals. Small, active cats often prefer to eat little and often.
• Check body condition every few weeks. On a thin-coated cat the ribs and waist are easy to see, so gain or loss shows early.
• Raise food slowly in winter only if the cat is losing condition, and bring it back down when the weather warms.

Fish oil and other fatty acid supplements are often suggested for skin. They may help some skin conditions, but we found no evidence specific to the Devon Rex, and a complete diet already supplies essential fatty acids. Ask the vet before adding them, particularly for a cat with the yeast problem described below.

Greasy skin and yeast

Devon Rex skin carries far more yeast than most cats' skin. When researchers sampled 21 healthy and 9 seborrhoeic Devon Rex cats, the yeast Malassezia pachydermatis grew from 26 of the 30. Even the healthy Devon Rex carried more of it in the armpits and groin than ordinary domestic shorthairs, and the cats with seborrhoea (greasy, inflamed skin) had larger populations still in the armpits, groin and claw folds.

Signs worth watching for:

• Greasy, waxy or brown residue on the skin of the armpits, groin or underside of the neck
• Dark, sticky material in the folds of skin around the claws and between the toes
• Redness, scaling, odor or itching at any of those sites
• Heavy brown wax in the ear canals

Mild greasiness can be handled with baths. Use a gentle cat shampoo, never human shampoo, and dry the cat thoroughly in a warm room, since a wet Devon Rex chills fast. How often varies: some cats need a bath every few weeks, others rarely. When the skin is red, itchy or smells, the cat needs a vet visit rather than more baths. In a small pilot study of six Devon Rex cats, oral itraconazole, an antifungal drug, reduced both the lesions and the yeast counts. Treatment choice and dosing belong with the vet.

Ears and claws

Check the ears weekly. Wipe visible wax from the outer ear with a cotton pad and an ear cleaner the vet recommends, and keep cotton swabs out of the canal. Black discharge, a strong smell, head shaking or scratching mean an examination, not more cleaning. Trim claws every one to two weeks, and wipe the claw folds if brown material collects there.

Congenital myasthenic syndrome

What older books call Devon Rex myopathy or "spasticity" is now known to be a congenital myasthenic syndrome, a fault in how nerves signal to muscles. A 2015 genetic study linked it to a variant in the COLQ gene, found in all affected cats tested. The same variant was found in affected Sphynx cats. Signs described in affected cats include:

• Weakness of the leg and trunk muscles
• Tiring quickly with exercise or play
• Megaesophagus, an enlarged and weak esophagus that lets food sit and come back up
• Weak throat muscles, so swallowing is difficult

Two practical points follow. First, weak swallowing and megaesophagus raise the risk of choking and of inhaling food, so affected cats need a feeding plan from their vet. This often means small meals of soft food, with the cat fed upright and kept upright for a while afterwards. Second, drugs called anticholinesterases, used for acquired myasthenia gravis, made the weakness worse in affected cats. A Devon Rex with muscle weakness should have this breed disorder considered before such drugs are tried.

The study estimated the variant's frequency in Devon Rex at about 2%. It is recessive, so a cat needs two copies to be affected, and carriers are healthy. A DNA test is available. Anyone buying a kitten can reasonably ask whether the parents were tested.

Blood type B

Genetic testing is essential for breeders, the CFA breed profile says, because of the high incidence of blood type B in the Devon Rex gene pool. Type B cats carry strong antibodies against type A blood. That matters in two situations. A type B queen mated to a type A tom can have type A kittens that absorb her antibodies from the first milk, which destroys their red blood cells in the first days of life. This is called neonatal isoerythrolysis. And a type B cat given type A blood in a transfusion can have a severe reaction. Every Devon Rex should have its blood type recorded, and breeders type both parents before mating.

Coat handling and sun

Rough brushing breaks the curled hairs; the CFA describes the coat as somewhat fragile, with occasional bare or suede-like areas. A soft brush, a grooming mitt or simply a hand stroked along the coat is enough, no more than about once a week. Pale, thinly haired skin on the ears, nose and belly can burn in strong sun, so limit long sunbathing sessions at windows in summer and keep cats with outdoor access in shade during the middle of the day. Ask the vet before using any sunscreen, because some human products contain ingredients that are toxic to cats if licked.

Activity, warmth and company

Devon Rex are active climbers and jumpers. Tall cat trees, wall shelves and a couple of short interactive play sessions each day with a wand toy give that energy an outlet, and puzzle feeders turn part of a meal into exercise. They also seek heat: a covered bed, a blanket to burrow under or a pet-safe heated pad in winter reduces the cold stress that comes with a sparse coat. According to the CFA, the breed becomes deeply attached to its owners and dislikes being left alone for long periods. For a household that is out all day, a second cat or a sitter makes a real difference.

Sources

1. The naked truth: Sphynx and Devon Rex cat breed mutations in KRT71. Mammalian Genome, 2010.
2. Devon Rex. The Cat Fanciers' Association.
3. Nutritional Requirements of Small Animals. Merck Veterinary Manual.
4. Carriage of Malassezia spp. yeasts in healthy and seborrhoeic Devon Rex cats. Medical Mycology, 2007.
5. Treatment of Malassezia pachydermatis-associated seborrhoeic dermatitis in Devon Rex cats with itraconazole: a pilot study. Veterinary Dermatology, 2007.
6. COLQ variant associated with Devon Rex and Sphynx feline hereditary myopathy. Animal Genetics, 2015.