Ringworm:

Symptoms:  Hair loss in affected areas, and scaly, red, circular patches that develop on the skin.  Hair becomes fragile and breaks easily.

Causes:  Ringworm is caused by a fungus.

Diagnosis:  Ringworm can be seen under ultraviolet light.

Treatment:  Medicated shampoos and dips should be used.  Bedding should be washed with Chlorox.  The vet may prescribe oral anti-fungal medications, or anti-fungal creams or ointments to be applied to the skin (wear gloves as ringworm is contagious to humans).  Severe cases may require shaving the hair in the infected area or the entire coat.

Hot Spots:

Symptoms:  Painful, inflamed area of the skin characterized by hair loss and inflammation.  Dogs may lick at hot spots continually.  Hot spots may have discharge or foul odor.

Causes:  Hot spots are bacterial skin infections (pyodermas).  They are often aggravated by other problems such as allergies, parasites, and poor grooming.

Diagnosis:  A vet can diagnose hot spots by sight, although further investigation into aggravating factors (such as parasites) may be needed.

Treatment:  Treatment should include both immediate treatment with medications such as antibiotics, steroids, medicated baths and dips, as well as the identification of the underlying cause of secondary pyodermas.  Foods and feeding conditions should be examined for potential allergies, and if parasites are suspected then a skin scraping should be made and appropriate action taken.

Mange:

Symptoms:  There are 2 main kinds of mange, Sarcoptic Mange (also known as "scabies") and Demodectic Mange (also called "demodex").  Mange is characterized by hair loss, hot spots, itching, pustules, and/or a foul odor.

Causes:  Both types of mange are caused by microscopic parasites (insects) called mites.  Different species of mites are responsible for the different types of mange.  Sarcoptic mange is highly contagious between animals, and can be transmitted to humans and nearly every kind of mammal.  Demodectic mange is not contagious, but the demodex mites are present on every animal.  Most animals have a sufficient immune system to fight off the mange and prevent them from becoming an infestation, but for some reason dogs with demodex infections seem to have insufficient immune systems for the task.  Some dogs outgrow demodex infections after puberty or after being spayed/neutered, but others will need to be observed their entire lives and kept from stress, fed quality foods, and kept well groomed.

Diagnosis:  A skin scraping will need to be done and the scraping viewed under a microscope to identify if mange mites are present. 

Treatment:  Treatment for both types of mange include dips to kill the parasites, and/or a regimen of ivermectin, either orally or via injection, until a subsequent skin scraping is negative.

Seborrhea:

Symptoms:  There are two types of seborrhea - seborrhea sicca is characterized by dry skin and scaling, and seborrhea oleosa which produces a greasy skin and undercoat.

Causes:  Seborrhea sicca may be an inherited disease in such breeds as German shephards, Irish setters, Labradors, and Dobermans.  It may also be caused by an insufficiency of thyroid hormones.  Seborrhea oleosa may be caused by an overabundance of thyroid hormones.  Either type may be caused by parasites, fungal or bacterial infections, or allergies.

Diagnosis:  No special tests are required to identify seborrhea.  Care should be taken, however, to rule out medical causes for the condition, such as thyroid issues.

Treatment:  Treatment of seborrhea sicca may be as simple as adding a moisturizing shampoo and conditioner to the groomng regimen, or adding vitamin E or fish oil supplements to the diet.  Seborrhea oleosa may require bathing with activated tar shampoos or shampoos with salicylic acid or sulfur.