Dermatology 101: How to approach a dermatology case

Obtaining a good history, physical examination and performing in-office diagnostics are necessary "starters" to each and every dermatology case. You will have more success in treating dermatology cases if you approach them systematically. Have a plan!

It sounds difficult-one more thing to have to do in a day with a millionthings to do. But, if you develop a step wise pattern to approaching patientswith dermatology problems, after awhile, the steps will become automatic.

If you haven't already realized it, dermatology cases take a lot of time!The number one step should be to have your receptionist schedule a few extraminutes or even double the time allowed for the appointment when he/shehears that the problem is skin related.

Allot enough time

Since most dermatology cases, perhaps more so than the other specialties,require obtaining a good history from the owner, extra time is necessaryto obtain this history. In large, multi-veterinarian practices, try andhave the same doctor see the patient each time. This is important for manyreasons but mostly to have one doctor manage the case and oversee all thetherapy that has been or is being administered.

Unfortunately, some cases suffer from overuse of steroids due to thefact that many doctors in the same practice see the patient in a short amountof time, and no one actually sits down and goes over the chart thoroughly.

Important points to consider are not only the chronic steroid use butseeing if a pattern is emerging regarding the time of year the patient isaffected and other factors such as multiple pets affected, human familymembers affected or whether or not the disease is steroid responsive.

History lesson

Obtaining a good history cannot be emphasized enough. As we all know,in some cases the client tells us everything except the answer to our question.It is up to us to ask the same question in different ways to obtain theanswer.

The first question I ask the owner is how long has the patient had theskin problem? At the same time, I am observing the age of the patient, breed,areas of the body affected and whether the patient is pruritic in the examroom.

Age of onset is important since atopy in most patients begins from 6months of age to 3-4 years old (some exceptions, of course). Atopy alsousually involves face, feet and rectal area, whereas a dog with pruritusand lesions in the lumbar and rear leg/groin areas is suspicious for fleaallergy dermatitis.

Since atopy is hereditary, we tend to see it in the same breeds, i.e.Retrievers, Terriers, herding dogs, Shepherds, oriental breeds, Spanielsand Dalmatians.

Are there other pets in the family and, if so, are they having skin problems?This question, if answered "yes," may indicate the presence ofa contagious disease like ectoparasites. Also consider if the pet is exposedto other animals either via grooming or kenneling because exposure to ectoparasitescan be present in those environments.

Along the same line of ectoparasite exposure, the question of the homesetting should be asked-does the pet live in a rural setting? Allowed toroam freely? Are there cats in the household that go outside, barn catsor does the dog go to the horse barn?

Once the age of onset, home setting and inquiry about other pets in thehousehold is made, questions should be asked about the seasonality of theproblem-nonseasonal, started seasonally and is now nonseasonal, or strictlyseasonal.

Response to past therapies should then be discussed. Was the pet responsiveto steroids? Antibiotics? If fleas were a problem, was the pet on a fleatreatment program and did the owner understand what was involved in a completeflea treatment?

Getting physical

The second step in solving the mystery is a thorough physical examination.This goes without saying no matter what the presentation of the patientis to the veterinarian.

Even though the patient may be seeing our office for a skin problem,we still check that patient thoroughly, particularly our geriatric patients.

I remember one middle-aged Basset Hound referred to us for skin testing.While examining the dog, I discovered she had lymphoma. The work up foratopy was postponed while the life-threatening disease was addressed.

A good physical examination is important for many reasons, one of whichis that certain medications cannot be prescribed when underlying diseasesare present.

In dermatology, some antihistamines can increase intraocular pressureand that would be contraindicated in dogs with glaucoma. Phenothiazine derivativesshould not be used in epileptics. Antifungals can be teratogenic and consequentlyshould not be used in animals going to be bred. Other aspects of the physicalexamination that yield clues to a dermatologic disease include alopecia.Is the pet pruritic and causing the alopecia or is the hair falling out?Have steroids been used recently as they cause a resting effect on the hairgrowth cycle resulting in hair loss with delayed regrowth.

Signs of iatrogenic or naturally occurring Cushing's disease includea pot-bellied appearance, thin skin that bruises easily with visible vesselsparticularly on the abdomen, a fine "peeling" of the skin andrecurrent bacterial pyoderma. Conversely hypothyroid patients may have athickened feel to the skin, appear depressed "tragic facies",bilaterally symmetrical alopecia with hyperpigmentation, and lack of undercoatwith hair loss beginning over points of wear. With either disease, the signsand symptoms can be extremely subtle, particularly early in the disease.

Diagnostics

There are many in-office diagnostics in dermatology that take very littletime and can yield quite a bit of information. Every pet that we see getscombed, scraped and smeared. Combings are performed with a flea comb notonly looking for fleas or flea dirt, but also to pick up Cheyletiella mites,lice, poultry mites or feline demodex gatoi (lives superficially).

The combings, consisting of hair and dander, are then observed underthe microscope in oil under low power. It is important that the patientwas not recently bathed prior to the appointment or the ectoparasite willnot be found.

Also consider that you are seeing the patient that is affected with theskin problem when another pet at home may be asymptomatic. Cheyletiellamites can involve asymptomatic carriers, so it may be necessary to see thepet without the skin problem to thoroughly rule this out. Skin scrapingsshould also be performed on all patients particularly in areas of crusting,scaling or alopecia.

If you do nothing else, be sure to perform skin scrapings to rule outdemodex or scabies. Scrapings are placed in oil, topped with a cover slipand observed under low power. Skin and ear smears obtained from nailbeds,ears and skin folds yield the presence of microorganisms such as yeast andbacteria. The smears are performed using Q-tips or scalpel blades and pressedinto a glass slide which is heat fixed then stained with Dif-Quik.

Ear smears tend to yield the most rapid information as to which microorganismsand in what amounts are present in the existing ear infection. Ear smearsin oil will detect ear mites or demodex mites affecting the ear canal. Donot confuse an ear smear with an ear culture!

An ear smear yields instant information about what is there and in whatamounts, whereas an ear culture takes at least three days to gain results.Ear cultures should be performed when rod bacteria are present as an antibioticsensitivity is necessary to see what the bacteria will respond to. Culturesshould also be performed when an existing treatment is not successful.

Dermatology 101

Dermatology 101 may sound elementary but if it gets you in the habitof approaching a dermatology problem with a plan, your outcome will be moresuccessful. It is time intensive because a good history and physical examinationare absolutely necessary, yet performing the in-house diagnostics mentionedabove take very little time.

If you do not feel familiar with performing ear smears or skin smears-startdoing it! Along with a dermatology or cytology book to guide you, you willbe surprised at the information cytology yields. The best way to becomegood at it is to start doing it on each patient you see. You can doublecheck yourself by submitting some of your slides to your local pathologist. M

Dr. Jeromin is a pharmacist and veterinary dermatologistin private practice in Cleveland, Ohio. She is a 1989 graduate of The OhioState University College of Veterinary Medicine and an adjunct professorat Case Western Reserve University's College of Medicine in Cleveland.