Primary Skin Lesions in Dogs
A skin lesion is any type of abnormality on the skin. A primary skin lesion on dogs is any type of lesion that comes as a direct result of an underlying disease. There are eight different types of primary skin lesions: macule (or patch), papule (or plaque), nodule, tumor, cyst, pustule (or abscess), wheal (or angioedema) and vesicle (or bulla). To diagnose the cause for the lesions, the veterinarian may need to look at scrapings or biopsies of the lesions. Treatment can involve ointments, medicated baths or oral medications, depending on the cause. Lesions will often lead to bacterial infections, so the dog will often be put on antibiotics as well. Dogs who have open sores should not be allowed in water because of the added risk of infection and the risk of spreading the disease that has caused the lesions.
-
Macule and Patch
-
Macules and patches are characterized by an area of the skin that has changed color. If it is no more than 1 cm in diameter, it is considered a macule. If it is greater than 1 cm, it is considered a patch.
Papules and Plaques
-
A papule is a raised portion of the skin that is solid and less than 1 cm in diameter. A plaque is larger and has a flat top. It is formed when papules are grouped together. A purpura is a type of papule that is formed when there is bleeding in the skin, and it is characterized by a reddish color.
-
Nodule
-
A nodule is similar to a papule except that it is greater than 1 cm in diameter and usually grows deeper into the skin.
Tumors and Cysts
-
A tumor is an abnormal enlargement of tissue that may involve any part of the skin as well as the underlying tissue. A cyst is often confused with a tumor, but it is a cavity that can contain fluid or solid material. It is smooth to the touch, and can be either compressible or solid depending on what it contains.
Pustules and Abscesses
-
A pustule is a small, raised lesion that is filled with pus. It is usually found between the layers of skin or in the hair follicles. An abscess also has pus in it. It is a soft, compressible lesion that forms as a result of pus accumulating just below the skin.
Wheals and Angioedemas
-
A wheal is a raised lesion with a flat top. It consists of edema, which is an unusual collection of water in the body, that quickly appears and disappears within a matter of minutes or hours. An angioedema is similar to a wheal except that the edema is deeper in the skin, which results in more diffuse swelling.
Vesicles and Bullas
-
A vesicle is a raised lesion that is filled with clear liquid that is smaller than 1 cm in diameter. This is commonly referred to as a blister. If it is greater than 1 cm in diameter, it is referred to as a bulla.
-
