Lick Granuloma (Acral lick dermatitis or ALD)
Dr. Rosanna Marsalla
Lick granuloma, also kown as acral lick dermatitis (ALD), Acral Lick Granuloma (ALG) or Acral Lick Furunculosis (ALF), is a common condition observed in large, active dogs in which the dog licks an area excessively, usually on the front leg, until a raised, firm ulcerated lesion is formed. These lesions are prone to infections, which make them itchier and itchier, which then leads to a self-perpetuating cycle of itching and licking. The term "acral" refers to the peripheral portion of an extremity. Deep skin scrapings and fungal cultures are necessary in all cases.
Many underlying diseases are responsible for this condition. It could be caused by psychological and behavioral factor or by skin and internal diseases. Allergies, endocrine disease, parasitic, bacterial and fungal diseases may cause lick granulomas. Interestingly, allergy to flea bites may also be a cause. Aggressive flea control is recommended in flea-sensitive individuals. In other cases, a change in the environment, a stressful situation or a change in the work schedule of the owner could be the trigger.
Sometimes the granuloma occurs in an area of a previous trauma like a fracture and that may be triggered by an abnormal sensation in the skin. In other cases, the excessive licking may be a sign of pain. Arthritis may be evident in the underlying joint.
It is important that the underlying case is identified and addressed in order to resolve this frustrating condition.
Several diagnostic tests are necessary to confirm a diagnosis of lick granuloma and investigate the underlying cause.
Skin biopsies and cultures of the affected tissue are also important tests, because most of these lesions are infected and it is important to identify the organism responsible for the infection and establish an effective therapy.
If a psychological component is identified it is important that all efforts are made to correct the problem. In some cases, the death of a pet may trigger the problem. In those cases it may be useful to introduce another pet in the house so that the affected animal has a playmate and is distracted, especially when the owner is not at home.
It is important to allocate enough time for exercise and playing especially in large breed dogs, which are very active. Long walks are always very helpful. If the cause is the introduction of another pet or the arrival of a baby in the house, it is important to pay more attention to the older animal so that he/she does not feel left out.
As most lesions are secondarily infected you will need to administer an antibiotic for a prolonged period of time, usually 2-3 months. Infections are usually very deep and it takes some time before the are completely resolved.
Symptomatic therapy could be tried to discourage the licking. That includes the use of systemic and topical medications. Systemic medications are usually antidepressant or anti-anxiety drugs. It is important that these medications are considered as a substitute for the identification of the underlying cause. They should be used for a short period of time to help break the cycle. They have the potential of causing serious adverse effects and they are quite expensive. A prescription is required for these medications.
The safest topical therapy that could be tried on these lesions is capsaicin (0.25 percent). It is available as an over the counter product in drug stores, as treatment for pain and pruritus (itching) in people. It works by depleting the skin of the molecules responsible for the transmission of these sensations. It should be applied 2-3 times daily for a few weeks before improvement is noted. Some individuals may build sensitivity to this medication thus if worsening is noted, this therapy should be discontinued.
Lotions with a bitter taste are usually not strong enough to prevent licking. Elizabethan collars may be necessary to reduce licking while the medications are allowed take effect.