Ask the vet: Summer Eczema/ Summer Itch.

Is your horse feeling itchy? Maybe it's the season . . . Join us in AugustAAEP expert, Dr. Frank Reilly, answers your questions concerning your horse's summer itches.

1
Question: I have a Clydesdale mare with sweet itch. This spring and summer I was able to keep the itching at bay for the most part with heavy, twice a day, Permethrin spray. In the summer, she goes out at night because she stays in during the day to avoid the Texas heat. However, these past two weeks, she has come in with evidence of scratching her face and neck a lot, which seems like a reaction to something else besides culicoides. It is hot and dry in Texas in August and not favorable for culicoides breeding. Is it another insect allergy or could she be allergic to something else? I suspect she also has other allergies. What types of food allergies can horses have? Is it effective to give a corticosteroid shot in the spring at the first sign of itching, as well as periodic shots instead of daily steroid? I'm aware of the side effects but I'm wondering if the benefit of giving the lowest possible dose to control the itching cascade would outweigh the risks.

I read your recommendations about baths, sprays and herbal supplements. What is the best herbal anti-inflammatory combination?
Answer: 
Culicoides bite at night, so when you are having problems at night, it is likely them.Yes, many folks have to do night turnout due to heat. Also, there are over 20 species of culicoides, that said, your horse can be allergic to many different species and one of them might have moved in recently or had a population explosion and is overwhelming the skin. 


You need to apply strong spray on a paper towel and wipe the face, ears and neck. Also, make sure your spray is high in piperonyl as this allows pythrerins/permethrin to work better.


I would add omega 3's to her diet to help the skin. Also, search or Google "equine summer eczema herbals" for natural oral formulas  to help her skin as there are many choices.
2
Question: My 15-year-old Morab palomino has developed a terrible hypersensitivity to both vaccines and now the bugs (and even some weeds) of spring and summer and has had terrible outbreaks of hives! At present, he is on a daily dose of 5 Hydroxizine tabs AM/PM after initial loading doses to get the reaction down. Recently, he has become lethargic and, while his coat is incredibly golden (having been covered all summer), his gums are pale and his mane and tail are slowly falling out. He is on an Omega supplement and, while I know it helps, I cannot seem to get him over this slump. Blood was drawn and he is only mildly anemic. The veterinarian thinks he may have developed a selenium toxicity because of the mane and tail hair loss symptom, which started about 3 weeks ago. I have tried to come up with a number for the selenium content in his feed and it may be around 3.5 mg - feed and supplements considered - and we are in Northern Illinois. While this seems high to me, I have read that 5 mg is the high end for this area. He is so uncomfortable, and now with the suggestion of a possible selenium toxicity - I don't know what to do and how to treat him. I have eliminated all possible sources of selenium except the omega supplement as of this week - that sel. value is .8 - and it helps with the itchiness. This is a terrible summer for bugs!
Answer: 
You are describing several allergy events in your Morab. Allergic reactions to insects, usually culicoides, resulting in equine summer eczema (itching, skin crusts, rubbing, hair loss...) AND food allergy to weeds resulting in hives. Horses that are hyper-reactive to these (one or both), often are more reactive to vaccines. At vaccine time, split up into 3 sessions 1 week apart (so less antigen load) and 2 hours prior to administering the vaccines, give banamine and pyrilamine in the vein. By having these medications on board, prior to vaccination, really helps. Also, avoid giving vaccines in the neck. Instead, use that big gluteal on the hind end.

Next, the insects. You need to treat this condition using a strong fly spray 2x a day (culicoides eat at dusk to dawn but regular flies attack damaged skin in morning) at dusk and morning. He also should be bathed 3x a week to remove urine attraction (culicoides are 30x more attracted to horse urine than cattle urine). Oral herbs can also be given daily to lessen reactions. Your omega supplement is helpful due to omega 3's, which help skin quality, but it's not going to be able to stand alone. Your horse needs a barrier system (spray) and also consider night stalling with 2 fans to blow away culicoides since they are weak fliers. Your mane and tail hair loss is very common in equine summer eczema.

Selenium toxicity is rare and Illinois, from studies with corn, show that area is actually low in selenium. Yes, 5mg is the top level. I would run a selenium blood level test (do not use sst tubes with gel as these create false low numbers due to selenium trapped in gel) and submit the spun down serum on ice packs to New Boltons Toxicology Lab(610-444-5800). The lab can tell you blood levels for peace of mind, but I bet they are fine. Your Omega supplement is fine and not a large selenium source. Remember, on your feed label, for example, if its 2ppm selenium, that means 2 mg selenium for every 2.2 pounds of feed. If feeding 1 pound of feed, then its about only 1mg selenium.

Your hydroxyzine is a antihistamine but also has side effects of being a tranquilizer and can make your horse drowsy. Your anemia requires your vet to go over your feeding program and double check your deworming program to ensure parasites are not leading to anemia.
3
Question: I have a mare with anhydrous, which I am treating with a product from Platinum with success, but I am still dealing with a dry coat and itching. I use a coat conditioning supplement in her feed but still have to deal with this issue. Any suggestions?
Answer: 
The Refresh product from Platinum is electrolytes, vitamins and amino acids, so the addition of omega-3's are ok to add for added coat condition. Including a 1/4 cup of ground flax seed, once a day, for a 1000-pound horse is helpful. Poor coats also can be from parasites. Go over your deworming schedule  with your veterinarian to ensure you are not leaning too heavy on fecal tests, which miss tapeworms, bots and encysted strongyles. Also, the addition of a ration balancer with about 30% protein helps skin, which is mostly protein.
4
Question: My 6-year-old Morab mare has evidenced allergic dermatitis the two summers that I have owned her. She was given initial dexamethazone injections and then daily prednisone tablets. I also shampoo her with EquiShield shampoo, spray with Genesis spray and fly spray and give Wellactin omega-3 oil. She is better, but not cured. We are considering having CSU vets do immunotherapy after fly season and after she is off steroids. Is there any reason to be optimistic that immunotherapy will cure her?
Answer: 
For certain conditons, immunotherapy can work (i.e. stems cells into injured tissue), but for allergy issues, it is difficult to say allergy shots are effective most of the time (and there is the expense). For example, culicoide (#1 cause of allergic skin itching in horses) gnats come in over 20 species. Your horse will be tested for 1-2 of those, but could have problems with 5 out of 20 for example. Often, horses are ok until the population of the allergic gnat overwhelms the immune system. You have many good points in your program:


1. Baths--horse urine is 30x more attractive to these gnats than cattle urine. Bathe your horse three times a week, as once a week will not work. Any shampoo works well, even dawn dish soap.


2. Omega-3--wellactin and fish oil are great, but add flax to the mix (highest omega-3 product in world as well as economical). Take 1/4 cup flax seed, grind in coffee grinder (K-mart has them for about $15) and feed once a day. Flax seed must be ground to be effective.


3. Genesis spray (topical steroid spray) + dexamethasone shots + prednisone tablets all are used to control inflammatory reaction AFTER the bite. This tells you that the barrier system being used is failing. Your spray is not strong enough and its not being used enough. All fly sprays degrade in sunlight and gnats start biting at dusk, so you need to spray twice at day and dusk and morning (morning spray can help stop other pests from attacking damaged skin).


4. Consider flysheets (wash once a week to avoid urine attraction) and night stalling with two fans blowing as culicoides are tiny and weak fliers. Fans and sheets are barriers on top of a better fly spray and more applying of it.


5. Try some of these added management ideas and keep me posted.
5
Question: Through the years, I have had several horses, as well as noted clients horses, that loose mane hair on the underside of the mane. This causes a thinning of the mane. The area is slightly flaky but does not appear red or inflamed. The flakiness is not more than the normal appearing thicker mane. No history of rubbing this area of the neck, and the condition does not appear to bother the horse at all. Any ideas what causes this or if there is a way to encourage mane hair growth in this area once it happens?
Answer: 
Often, when I am not sure of what is causing a skin problem specifically, I will treat the most common skin conditions and get good results; what exactly was the problem goes undiagnosed, but the horse improves.

1. Insect hypersensitivity mild case----2x day spraying of a strong fly spray + omega-3 oil via 1/4 cup flax seed then ground in a coffee grinder (K-mart for $15) +  bathing area 3x a week with any shampoo. I have luck with dawn dish soap + oral herbals that keep inflammation down.

2. Parasites--I will do Equimax paste dewormer three weeks in a row (i.e. Monday, Monday, Monday).

Many horses skin problems are due to deworming schedules too dependent on fecals. Tapeworms, bots, encysted stronglyes can be missed on fecals and a lot not dewormed for 6+ months. By using this program also helps get many ectoparasites. I will have the owner then go every 60 days with dewormers during the season of hair loss.

3. Sunshine increase--many of these horses get mild bacterial/fungal hair problems that sunlight helps control.

4. Nutrition---I will add more protein to the diet. There are many ration balancers with higher protein and zinc to help immune system of skin. Three baking cups is equal to one pound given to a 1000-pound horse. Skin is mostly protein.

5. I figure if I can get the top 3 or 4 causes of skin problems, then I will get most cases- shotgunning some may say, but the above items are easy and economical to try.
6
Question: My horse gets itchy on his sheath. He then scratches it with his teeth, which causes swelling. If I put swat on him every other day it prevents this from happening. Are any of the anti-itch supplements useful? I was concerned because of the ingredients like calf thymus. Other ingredients of some of these supplements included diatamacious earth  as I don't want to give this to my horse.
Answer: 
Your horse has a insect hypersensitivity reaction to most likely culicoides gnat, the #1 cause of itching in horses. There are many thing that can help:

1. Strong fly spray sprayed on the sheath twice a day in dusk (when they come out to bite) and in morning when other flies attack damaged skin. You can spray sheath safely but do not spray directly on the penis. Blast the spray right up the groin, belly area as the spray will cover a larger area than ointment swat and gets way under between the legs better.

2. Bathe your horse three times a week as urine of horses is 30x more attractive these insects than cattle urine. Be sure to scrub the sheath area with medicated shampoo and rinse well. You may use a medicated shampoo for three weeks then after that any shampoo, even dawn dish soap. If you find yourself in a pinch after a ride, at least hose off the sheath area with water and bath next day.

3. Consider night stalling with two fans blowing in the stall as this keep the insects away.

4. Fly sheets are of little help in this area.

5. Consider daily herbal anti-inflammatory therapy.

6. Add omega 3's to the diet including 1/4 cup of ground flax seed (#1 for omega 3 content of any product) or use chia seed (no need to grind) or a daily dose of 30cc orally of wheat germ oil. Purchase 100% Wheat germ oil and not the blend, which is 1/2 corn oil. Some horses may need an iv/im shot of antihistamines/steroids as a one time therapy for quick relief, but keep dose low. If your horse has Cushing's or insulin resistance (IR), your veterinarian will likely use only antihistamines.

7. If area looks infected from wounds, call your veterinarian for antibiotics--if your horse is not dropping out his penis fully and the area is getting sprayed with urine, your veterinarian will sedate the horse and check to see what the problem is. Get your horse's sheath cleaned with clean water every few months if he is one of those horses that accumulate a lot of debris.
7
Question: I have three horses stabled in a barn with a horse that was recently diagnosed with "herpes". His symptoms are lesions on both of his ears and his chest. Their reason for how he contracted the disease was from a fly bite that bit a cow and then bit him. I have two mares and a stallion in this barn and I am worried because this horse has not been isolated and is stalled right next to one of the mares that was scheduled for the breeding shed in the spring. Is this herpes and will my horses be effected?
Answer: 
What you are describing is a sarcoid, which will cause small benign tumors on the skin. Some will be nodular, some will be rough like sandpape and some will be in pinhead-like bumps. This problem appears from the latest research to be most likely from a form of papilloma virus very similar to that of cow papilloma. A papilloma virus is a different class than the herpes virus, therefore; your breeding should go on and do well. The one drawback of the sarcoid is its ability to topically spread on the skin to other places on that horse, but also when these areas become raw and bloody, spread to other horses. Sarcoids are the most common skin tumor of horses, but are benign, meaning they do not move internally or lead to loss of life. Many horse operations have sarcoid horses in a herd with no resulting transfer to other horses. There are many different treatments for sarcoids and your farm veterinarian can direct you to the ones they have found to be the best for the type this horse has on its chest and ears.
8
Question: I have a mare that cannot stop rubbing. In the past, she has almost rubbed her entire tail off and most of the hair on her hindquarters. I have covered most things so she can't rub her tail off. She chews on her legs a lot. I keep fly spray on the best I can and have a barn fan in the shed where she spends nights. I know she is miserable, but is there anything else I can do? My other horses are not as bothered.
Answer: 
Yes, your horse has an insect hypersensitivity allergy, so other horses are fine but she is likel unhappy.

Please go to my other responses to see program---your fans at night are great but make sure at least two of them are blowing so there is a great deal of turbulence as culicoides are tiny and have a hard time traveling through these conditions.

You also need to spray twice with a strong fly spray(doing right on tail but also entire body and up groin also), a good deworming program, include omega 3's within her current diet, if bathing, she will need to be bathed three times a week to remove attraction, possible herbal anti-inflammatories added. Unfortunately, no one thing will stop it and will require a gang tackling to get results. I like using a medicated shampoo for 30 days then go to any shampoo, even dawn dish soap, works well.
9
Question: I purchased a Tennessee Walking horse (light bay) this May. He had just a little dandruff in his mane, but it cleared up. Now he has lost two long chunks of his mane from scratching. In among the roots of the hairs are small red areas and some light scabbing. He also has flaking at the top area of his mane. I am currently giving him a top-dressing bug-off additive and it seems to be working for most of his body, but he has rubbed his chest area and now has small raw areas. I have tried horse products for itchiness, but many of them had sulfur and he welted from them. Head and Shoulders for itchy scalps seems to be working for the mane and tail issues if I use it every day. I am putting an ointment on his chest to help it heal and to keep small insects away. I use Ultrashield on his body and legs where there doesn't seem to be a problem. Also, he has managed to scratch both sides of his sheath with his hooves, so that there are raw spots there as well. I am using the ointment there as well. He goes out at 4am and comes in at 10:30am as the Florida heat is terrible right now and he likes the stall fans, which probably help keep the bugs at bay. I am at my wits end trying to make him comfortable.
Answer: 
Have your veterinarian look over chunks of hair area as this might be a combination of rain rot (hair out in paint brushs like chunks with bacterial pus under) and insect hypersensitivity.Your doctor may need to put your horse on antibiotics for a small time.Your shampooing is a great idea since the culicoides are very attracted to urine, but you must bath 3x a week at a minimum. Currently, in an outbreak, you are using a medicated shampoo, which is perfect, as you need to avoid secondary bacterial infections from bites or from horse self mutilating skin from rubbing on posts, kicking himself with back feet into his own sheath. Next, your spray is good, but it is not being used correctly if he is kicking his sheath. You can spray these right onto the sheath (not on penis) on both sides. Give him a blast of fly spray twice a day at dusk and in the morning over the entire body including mane. Your spot on will not protect the entire body as it is NOT in the same class of medications as spot on dog products. The horse spot on is only pyrethrins or derivatives of that. Also, add omega 3's to the diet and ensure you are deworming correctly at least every 60 days with these type horses--do not rely on fecal tests--see my last response for dosing omegas and dewormers. Remember culicoides eat at nite, so nite turnout requires daily dusk fly spray over the entire body. However, many horse owners in Florida are doing as you are with nite turnout due to hot daytime and providing a stall he can walk into with fans to blow insects away at nite or a shed with fans in the corners to further avoid culicoides since fly sheets in hot weather are difficult.
10
Question: I have a middle-aged pony that in the summer, particularly July and August, starts to itch. Itching is mainly on her face, neck and chest. Her once beautiful mane becomes very brittle and breaks off as does her forelock and tail. Her tail also begins to look like a honey comb with all the dead skin build up. I have tried the usual shampoos, conditioners sprays, ointment, fly sheets, feed additives, etc. I have not done blood workups on her. Is this something I should try and what tests should be run?
Answer: 
What your pony has is a specific allergy to a specific insect or group of insects that move into your area during this time, OR are there but reproduce rapidly at that time so the numbers are overwhelming. Remember, there are over 20 species of culicoides and the populations change and your horse might not be allergic to one type of culicoides but is to another that moves into that area.

I would suggest several items to "combo- tackle" the problem--1 or 2 things will fail:

1. Make sure you are deworming every 60 days with ivermectin products from May to Sept (i.e., May, July, Sept) as you will need the immune system at peak performance (wormy horses have poor coats and poor protective barriers). 

2. Add omega-3 products shown to help skin in small animals---flax seed (you may have to grind up to 1/4 cup of seeds a day, every day as flax is highest in omegas), or chia seed at 1/8th of a cup a day (no grinding) or wheat germ oil at 30cc a day (NOT wheat germ oil blend which is 1/2 corn oil--get 100% wheat germ oil).

3. Sprays---2x day at dusk and in morning--use with pyrethrins, permethrin,  piperonyl stabilizer. No fly spray lasts over 12 hrs as sunlight breaks them down. Be sure to pay attention and spray on mane and spray a clean paper towel with two pumps and wipe her face. It is very important to know that often spray is weak or not applied at right times or not done twice a day. Why should you spray during the day? Damaged skin attracts other flies.


4.Oral herbals with anti-inflammatory ability can help.



5.Yes, shampoos can help but must be done 3x a week for effect since the urine of horses is very attractive to culicoides (30x more then cattle urine). Also, blankets that get dirt/urine on them can be a problem as they need to be cleaned once a week or put a new one on.

6. Stall at night with fans as culicoides are tiny and poor fliers and eat at dusk to dawn.
11
Question: I recently purchased a 13-year-old Tennessee Walking horse that was on 24-hour turnout. Now he has a stall and is turned out 7-10 hours per day. He has managed to scratch out part of his long mane (on trees, walls,etc.) When I look between the hair roots of his missing mane area is it red and slightly scabby. Also, along the opposite side of his neck where his mane originates, there are faintly bumpy areas where there are dead skin flakes (gray in color) that are rising from his skin's surface. I am using a very very fine toothed comb to remove these flakes and separate them from his coat. There is no loss of hair, just these flakes rising from his skin's surface. I am at a loss as what to do for him. His tail, at the base, has also flaked before, but I have gotten this under control using Micro-Tek spray, however, it doesn't seem to be working for his mane area....HELP!!!!!
Answer: 
The most common allergic condition of the horse is insect hypersensitivity and the #1 cause of that is allergic reaction to the bite of culicoides---this can produce an itch that has your horse self-mutilating its skin via vigorous rubbing on fences, poles, trees like you are seeing. There are several steps to take to help your horse:

1. Apply a strong fly spray 2x a day---culicoides bite from dusk to dawn so apply once at dusk, but also in morning---damaged skin is attractive to other bugs during the day.

2. Bathe 3x week--the urine of the horse is very attractive to culicoides--when they roll, they place urinary components into the mane. The baths also soothe damaged skin by preventing secondary infections.

3. Add omega 3 to diet via flax seed (ground), chia seed or wheat germ oil--shown to help soothe skin.

4.Go over your deworming program with your veterinarian----ensure onchocerca is not an issue--ivermectins also can be of help in lice, mite problems (given multiple times over weeks).

5. Nite time stalling with fans would help avoid culicoides due to weak fliers and eat at nite. Remove any old standing water that breed culicoides (tires with water in them, stagnant water). Please remember that these insects can fly up to one mile, therefore; if your neighbors have standing water, it will be tough to stop.

6.Fly sheets may also benefit--- another barrier on top of fly spray, to protect--are ones that cover the mane.

7.Your veterinarian also can do a skin scraping of the area.
12
Question: The use of cortocosteroids (oral prednisolone or injectable Vetalog) are invariably recommended by my veterinarian to treat sweet itch in my 20-year-old mare with worsening symptoms each season. Which horses will develop laminitis in response to steroid therapy? Is the horse more at risk of doing so each subsequent year? How can the risk be reduced?
Answer: 
At times, in severe outbreaks of summer eczema, steroids may be needed for one to two treatments to decrease inflammation and stop itching that is so bad the horse mutilates itself by rubbing on fence posts or crawling on the ground, rubbing its belly over rocks. Steroids for this small amount of time avoid problems with possible triggering of insulin resistance surging or laminitis episodes in horses with Isulin Resistance (IR) and Cushing's. Long term, daily steroids are not an option in horses with IR, Cushing's, past laminitis and studies have shown even in normal horses, IR can be seen in long-term steroid use over 21 days. The goal is to avoid the active case by management---fans blow culicoides away easily as they begin biting at dusk to dawn. That said, stalling at nite with fans helps. The 2x day application of strong fly sprays is mandatory to avoid the bites. The addition of omega-3 supplements such as flax seed (ground), chia seed or wheat germ oil has been shown to help skin conditions and skin health. Baths given 3x a week has been shown to be very helpful in reducing bites as the horse's urine is very attractive to these insects. Barriers of fly sheets can help, but they must be cleaned regularly of horse urine picked up when they roll. The use of daily antihistamines has been used, but like steroids, this is only treating the horse after its bitten, which is not the goal.