Wandering Willie Allergies in Dogs

Species of this plant grow wild worldwide and are often found in wooded areas and fields. They are used as an ornamental plant in homes and gardens, but can become pests when they grow in areas where crops are being cultivated. The sap from the wandering willie plant typically causes an allergic contact dermatitis when in comes into contact with bare skin. This can occur just from brushing up against the plant.

If your pet has an encounter with the wandering willie plant and is displaying irritation of the skin, see your veterinarian in order to provide relief.

Wandering willie is the name given to a few species of plants in the Tradescantia family, more commonly known as wandering jew and spiderwort. Allergic contact dermatitis is possible with exposure.

Skin reactions are often concentrated around the face, groin, under the front legs, or between the toes. Allergic reactions to the wandering willie plant often occur at the contact point as well.

• Bald patches
• Blister-like lesions
• Chronic ear infections
• Chronically inflamed feet
• Face rubbing
• Head shaking
• Hives
• Obsessive licking
• Paw biting
• Skin infections
• Skin rashes
• Ulcerations on skin

Types

There are three plants that are most commonly referred to as wandering willie. They each sprout small three-petaled flowers in white, pink, or purple, but the foliage on each is quite different. 

Tradescantia fluminensis - The leaves of this plant are dark green and oval shaped with pointed tips; it is also known by several other names, including wandering jew, small-leaf spiderwort, and river spiderwort 

Tradescantia pallida - This variety is also called purple heart and purple queen; it can be distinguished from the others by its spear-like green leaves, fringed in red or purple 

Tradescantia zebrina - The broad pointed leaves on this variety of wandering willie have two broad, silver stripes adorning them; it is also known as inchplant

Skin allergies caused by exposure to the wandering willie plant are a result of an inappropriately aggressive response of specialized immune cells known as mast cells to a protein in the sap of the plant. The protein that stimulates the mast cells to release histamine is found throughout the plant, concentrated in its sap. The sap has a high likelihood of causing an allergic reaction in canines and humans. Histamine’s inflammatory effect is what causes the majority of the itching and swelling characteristic of an allergic response.

The allergy-related symptoms that your dog will be showing after exposure to the wandering willie may prompt your veterinarian to collect skin scrapings when doing the general physical. This is so that a microscopic evaluation of the skin cells, called cutaneous cytology, can be completed in order to search for problems like mites or yeast infections. Allergies to the plant sap will start at the contact site but can move to other areas of the skin, although reactions are often centered on the face and groin, as well as under the front legs and between the toes. 

A thorough history of your canine’s health and a timeline of symptoms can be extremely beneficial to an accurate diagnosis. If an environmental allergen is suspected, your pet’s doctor may recommend a patch test, also known as an intradermal skin test. Miniscule amounts of the suspected antigens are injected under the skin, inducing a localized reaction. 

Due to the large variety of plant-based allergens to test for, the results can be mixed. Many veterinarians prefer to diagnose which allergen is causing the reaction by eliminating suspected allergens from the environment first. Because wandering willie is known to cause allergic contact dermatitis, it should be suspected if it is growing in your garden or home.

Although antihistamines are generally effective in humans, they are only effective for twenty to thirty percent of canines and are prone to losing effectiveness over time. Salves and shampoos made with hydrocortisone may relieve the skin discomfort that your dog is experiencing due to the wandering willie allergy, although efforts should be made to keep your pet from licking off the preparation. 

If neither antihistamines or topical hydrocortisone are successful in reducing the allergy-related symptoms caused by the wandering willie plant, then corticosteroid injections or oral tablets may be warranted. Although these medications are usually very effective in reducing the signs of allergy, the side effects can be worrying. The long-term side-effects can contribute serious disorders such as diabetes and liver dysfunction, so concurrent monitoring of the blood chemistry levels may be required. These developments are often dose dependent, so the lowest effective dose of corticosteroid should always be employed. 

Another option for animals that are plagued by unavoidable or severe allergic reactions to this plant or other contact allergens, is injected immunotherapy. This is especially effective to treat reactions that are present for at least four to six months of the year and are resistant to antihistamines. Advancements in sublingual immunotherapy have been made, and recent trials are promising, but this option is not commonly available at this time.

If your dog has developed an allergy to the invasive wandering willie plant, removal of the plant from the environment, or restriction of the dog's access to it, is of paramount importance. Following the instructions that are given regarding oral and topical medication, including bathing requirements or dietary restrictions, should be followed faithfully and may need to be continued even after the symptoms are no longer apparent. Infections are a common occurrence with skin allergies, and antibiotics may be prescribed to combat any that do arise. It is important to give your pet the full measure of the antibiotics prescribed so that the infection does not rebound.