Labrador Retriever

Acral Lick Granuloma

An acral lick granuloma is a lesion, usually located on the distal part of one of the limbs of dogs, which is caused or worsened by the animal's obsessive licking of it. Damaged cells are believed to release pain-relieving endorphins that addict the dog to the licking and mutilation of the lesion.

The possible causes of the itching and licking behavior include:

Juvenile Cellulitis

Initial signs include swelling of the face (eyelids, lips and muzzle) that progresses to draining pustules and crusts. The earflaps and ear canals are often swollen and ooze pus. The lymph nodes often become swollen, especially those behind the jaw. The lesions may be painful and some puppies are lethargic, have a fever and won’t eat.

Reactive Histiocytosis

Cutaneous histiocytosis:  Lesions typically are multiple, red plaques or nodules that occur anywhere on the body.  Nodules may be ulcerated, but are not usually painful or itchy. Some dogs have lesions that remain confined to the nose, resulting in a “clown-nose” appearance.  Nodules may wax and wane, or regress and then appear elsewhere on the body. 
Systemic histiocytosis:  Clinical signs vary with the severity of the disease.  The cutaneous signs can be very similar to cutaneous histiocytosis, but nodules can involve the eyelids and nasal mucosa as well.