Coping with Sweet Itch

Coping with SweetItch

 

(By Pauline Williams, BSc, MSc,MA,VetMB, Cert EM (Int Med), MRCVS)

 

Sweet itch is a skin condition caused by an allergic reaction to midge bites (primarily Culicoides spp). It is also known as insect bite hypersensitivity or summer seasonal recurrent dermatitis, and can affect horses, ponies and donkeys all over the world according to the distribution of midges.

All animals are bitten by midges but only those that are allergic to the bites show clinical signs. There are different species of Culicoides which feed at different sites; some at the mane and withers, others at the tail and or belly and legs. The animal may be allergic to one or more species and therefore they may show signs on one area only, such as the tail or all over the body in severe cases.

Clinical Signs

Affected animals show varying degrees of pruritis (itchiness) which leads to self-trauma due to rubbing. The most common sites affected are the mane and tail but sometimes only the belly is affected and in severe cases the animal may show signs of all over the body including the legs. Rubbing leads to alopecia (hair loss), ulcers and bleeding with secondary crusts (scabs) and infection. Many of these changes are reversible out of season when there are much fewer midges. However in more chronic cases the skin can become hyper pigmented (blackened) and thickened with ridges, especially along the mane. Severely affected animals may lose weight due to chronic irritation and show behavioural changes from tail swishing, rolling, and rubbing the belly on the ground to being unrideable at the peak midge feeding times of the day (dusk and dawn).

If you are buying a pony that is said to be managed successfully by one of the different treatment options, you should be aware that a change in location may either improve or exacerbate the condition to a point that it is no longer manageable. Sweet itch sufferers may also deteriorate with age.

When buying a pony in the winter out of the midge season, in severe cases the thickening on the neck and tail head may still be evident. However, it is often difficult to detect animals which show milder signs or those that have been managed effectively through the summer. Often there is evidence of different hair length, particularly at the tail head, but it is important to ask the owners to declare if the pony suffers from the condition. At present, there is no reliable blood test or other allergy test to detect sweet itch sufferers out of season, but research is on-going.

Identifying Joint Disease

 Identifying Joint Disease

Joint pain can be mild to severe; even mild joint pain that is unnoticeable in terms of lameness to the rider can be performance limiting. A sore joint may stop a show jumper landing on the correct lead after the fence or it may cause the horse to roll unnecessary poles of higher fences. A dressage horse may show asymmetry of limb action during complex dressage movements. Polo ponies may find it difficult to stop and turn sharply and race horses with joint pain may be slower than their expected potential. Joint pain is as a result of joint inflammation, so left untreated some inflamed joints will settle down with rest. Some chronically inflamed joints go on to become osteoarthritic. Early identification of joint inflammation and appropriate treatment can reduce the chances of chronic joint pain and therefore poor performance and lameness issues.

 

Often riders will call and say they think there is a problem with a horse, and I now look at higher level competition horses on a regular basis to monitor for joint pain. The first thing is to ask the rider to describe the problems they think they are having. I then palpate the horse’s limbs for obvious filling of the joints, as in most cases an inflamed joint will have an effusion, which is where the inflamed lining of the joint produces an excess amount of fluid. Some effused joints can be identified by visual inspection as the joint bulges. In some instances, particularly with the fetlock joint, it is possible to feel a palpable thickening of the joint capsule. Some joints will feel warm to the touch.

 

The next step is to trot the horse up on a firm flat surface and see how it moves. One of the advantages of regular checks is the vet gets to know what it normal for the horse and is then able to spot subtle gait changes. Flexion tests are a valuable way of identifying a problem with a joint, most inflamed joints will result in lameness after flexion test. The horse will then be evaluated under saddle, on the lunge in a school and on a hard surface. The rider will be asked to demonstrate the problems they are having, this may be during complex dressage movements or jumping obstacles.

 

Often it is possible to identify a specific joint causing the problem by clinical examination, but a lot of the time it is necessary to anaesthetise or block sequentially joints on the limb in question. Once a joint is blocked the horse is put back in the situation that demonstrated the lameness the best, i.e. on the lunge, on the hard or flexion test. Often there is little for the vet to visually see and the response to blocking must be assessed by the rider.

Joint Disease Treatment

Joint Disease Treatment

Once the problem joint has been identified, the next step is to formulate a treatment plan. The first option is usually to medicate the joint with corticosteroids in combination with hyaluronic acid. There is often bad press given to the use of corticosteroids in horses, but the doses that are regarded as protective to the cartilage in the joint pose little risk of much talked about side effect of laminitis. Inappropriate use of corticosteroids in terms of dose rate and injecting too many joints at one time may result in problems but using corticosteroids would be regarded as routine by myself and many other vets. Corticosteroids cannot be used near the time of competition or the horse will come up positive on a drug test. As such we obey a withdrawal period, which depends on which drug is used. This means that horses that have repeated problems with joints and need medication to help also need a treatment plan worked out based on their competition schedule.

Arthroscopic surgery is an option for chronically diseased joints and is often carried out outside the competition season to allow time for recovery after the surgery. Shockwave can be a very valuable tool for treating some joints such as the flat weight bearing joint of the hocks, where chronic inflammation is called spavin. It is not completely clear how shockwave works, however it does have a desensitizing effect as well as stimulating blood flow by sending acoustic shockwaves through the tissue. Shockwave can also be a useful treatment for ligamentous problems around the joints.

When I am evaluating a horse with a joint problem an assessment of the foot balance is also made, and any findings are discussed with the yard farrier. Often, altering the shoeing will alleviate pain from within a joint, this is often the case with the hind feet and hock pain. It is also worth involving the physiotherapist in the treatment plan, as horses with chronic joint pain will have upper limb and back stiffness issues. The use of glucosamine based food supplements is a useful adjunct to the management of all sports horses, regardless of whether they have joint problems or not.

The key to managing a competition horse in terms of performance is not to wait until the horse is showing signs of lameness, but to identify subtle problems that can be affecting their performance and act before they become a bigger issue.

Laminitic Horse

Caring for the Laminitic Horse

(By Ed Lyall, BVetMed, CertEM (StudMed), MRCVS)

Laminitis is a painful condition involving inflammation of the laminae. In severe cases the laminae become inflamed all around the hoof resulting in uniform separation, when the limb is loaded the whole pedal  bone then ‘sinks’ within the hoof. The prognosis following rotation is much worse; radiographs are useful to identify what had actually happened.

Causes

There are several reasons why laminitis occurs and it is important to identify the cause so treatment can be carried out accordingly;

1. Equine metabolic syndrome (EMS) which is effectively a form of insulin resistance.
2. Cushing’s disease which many older horses and ponies are now diagnosed with.
3. Some form of sepsis or infection that result in the release of toxins within the body, such as colitis, colic surgery or retention of a portion of the placenta after foaling. Grain overload also falls into this category as the change in diet results in abnormal toxin producing bacteria colonising the gut.
4. Excessive loading of one limb due to injury to the opposite limb. 
5. Excessive exercise on hard ground.

Clinical Signs

Laminitis affects the front limbs more commonly that the back limbs, but one foot can be affected or even just the hind feet. The typical signs of laminitis include;

1. Abnormal stance – usually with the weight rocked back onto the heels and toes out in front off-loading the weight from the more painful toe region.
2. Often cases look very awkward on their hindlimbs, but this is a result of more load being taken by the back end.
3. Walk is reluctant with a toe slapping gait, where the heel is loaded before the toe. There will often be stiff, stilted gait when turning sharply on a hard surface.
4. Often soft footing will be favoured by the patient. Severe cases will lie down and be reluctant to get up.
5. From a clinical point of view the hoof capsule may be hot with a strong pulse palpable in the palmar digital arteries at the back of the fetlock and there will be a pain response on hoof tester pressure in the toe region.

If laminitis is suspected, the first thing to do is make sure there is a deep soft bed, administer pain killers in the form of phenylbutazone if available and then contact a vet for assistance. Laminitis is in many cases an emergency.

Treatment

This will comprise of the following:

1. Removal of shoes, shortening the toe to reduce the rotating effect of the deep digital flexor tendon.
2. Some form of frog support will then need to be applied, and this is to off load the weight from the painful hoof wall. 
3. If we know there has been a toxic episode then icing the feet can reduce the blood supply and prevent further toxins from reaching and damaging the laminae further.
4. Over the years many products have been tried to affect blood flow to the laminae, such as ACP and an ointment form of trinitroglycerine.
5. Phenylbutazone or a derivative is the main pain relief used.
6. Appropriate levels of exercise depending on response to therapy, initially strict rest, then more comfortable turn out in a small paddock may be allowed.
7. Once the initial laminitic incident is under control, then there are a multitude of types of shoes that can be applied to the feet from egg and heart bar shoes, reverse shoes, four point shoes with rails to clogs. The clogs have saved many horses’ lives recently and again are my favoured transition from strap on pads to more normal shoes.

Donkeys Come To AEH

“Freddie” (brown donkey) was admitted to The Arundel Equine Hospital in June for investigation of a mass. On the 12th June “Freddie” was referred for surgery; a segmental postototomy was performed on the distal aspect of the prepuce and the mass suspected sarcoid (melanoma) was removed.

Recovery from anaesthesia was excellent and following recuperation at the hospital “Freddie” along with his trusted friend “Tallulah” are now residing at The Donkey Sanctuary in Sidmouth, enjoying life by the sea.

"Freddie" (pictured right) and "Tallulah" with nurses Emma Poucher and Alanna Baker

September News

It has been a busy summer at The Arundel Equine Hospital; the stud vets have been no stop working with sport horse and racehorses during the breeding season.  There have been some interesting cases coming through the hospital and we have had vets attending race meetings at Goodwood, Brighton and Fontwell (a total of 45 meetings during the summer months) and covering the two International meetings at Hickstead. Rob van Pelt also attended Burghley Horse Trails. Alongside these fixtures we have provided veterinary cover for numerous local Pony Club and Riding Club events, South of England Show, point to points, polo matches etc. across the counties, not to mention delivering the regular 24/7 service.

Summer 2014 has seen a few changes to the Practice, we say goodbye to two of our Veterinary Assistants; Helen Webster, who on route to Ireland, is spending a stud season in Australia, and Sarah Allen, who is going to study a Masters in Epidemiology. We also say goodbye to intern, Camilla Woodward. We wish you all the very best of luck and you will be missed greatly. Which takes us to welcome two new Veterinary Assistants to the fold, Chris Baldwin, who will be working in the South of the Practice, Chris has recently finished a 2 year internship at Newmarket Equine Hospital and, Emma Davis, who will be working in the North of the Practice and has returned South from spending 2 years working in Scotland. We also welcome Andrea Giavitto as the new hospital intern.

VWH – 20th July

Vet's with Horsepower

We left Sandefjord early on Thursday morning to cross on the Moss ferry into Sweden. After a brief stop for coffee with Svein we had a long ride down through Sweden eventually crossing from Malmo to Copenhagen over the 8km bridge. We arrived to a great reception from Denis and Gaby from Copenhagen university and their family and were entertained well at their lovely cottage. On Friday morning we headed into the college equine site for a day of lectures, well attended by the Danish horse vets. We also received a tour of the college campus to view their surgical facilities and have a look at some of the inpatients, both horses and lambs! 

On Saturday morning we left once again this time on a final stretch home. All motorway again across Denmark to Esbjerg where we picked up the ferry to Harwich in England. From here everyone departed to home.

It has been a great experience to be involved in the Horsepower tour this year. During the trip it was explained to the delegates just where their donations have been going. For just £150 the Smile train charity can help repair children with cleft palates who without the opportunity are often unable to get ahead in any form of their lives and often die prematurely living in squalor. By saving donkeys in Gambia we stop the young children having to carry the water daily instead. It feels a privilege to have been involved and I've been left with a real sense of trying to give something back. Together we have raised over £95000 for the two charities.
Just need to try to avoid sitting down for a week or two! 
Andy

VWH – 17th July

Thursday 17th July

Every now and then something extraordinary happens that reminds us of just how amazing people can be. We were lucky enough to be part of an incredible act of individual and collective generosity last night at the Norwegian lectures. In an emotional speech which had almost everyone in the room in tears at end of the lectures, the incredibly charismatic and unbelievably dedicated and hard working local organiser Dr Svein Bakke presented a cheque for a massive £20,000 (211,000 Kr) to the Vets with Horsepower team. This huge amount of money was raised by the Norwegian delegates (who paid to see the lectures) and from sponsorship raised by Dr Bakke (the sponsors can be found on the Vets with Horsepower Facebook page and the Virgin Money Giving site). This is the largest donation from any venue we have visited and takes the total raised for Smile Train and The Gambia Horse and Donkey Trust to over £80,000!

To put the Norwegian donation into context, this is enough to pay for life saving cleft palate and hair lip surgery on 100 children and vaccinate 2,500 horses or donkeys against tetanus. Go Svein, Go Norway and Go Horsepower!