How Long Do Allergic Skin Reactions in Dogs Last?

Allergic skin reactions in dogs can last from 2 to 3 weeks, depending upon the allergen. An allergic reaction is the body’s immune system’s response to an allergen, causing an over reaction. The immune system is the body’s system that protects the body from foreign invaders and potentially infectious materials. Allergies and the resulting reactions can last a lifetime.

General Symptoms of Allergic Skin Reactions in Dogs

The following is a list of general symptoms of allergies, but other symptoms may present themselves as well.

  • Vomiting
  • Diarrhea
  • Chewing of affected area
  • Constant licking
  • Sneezing
  • Itching
  • Increased scratching
  • Itchy, runny eyes
  • Inflammation
  • Red scabs
  • Hair loss
  • Difficulty breathing
  • Pruritus—itchy, swollen skin

The allergic reaction is caused by the body’s attempt to rid itself of the allergen by increasing the amount of white blood cells, which attack foreign bodies, and histamines into the bloodstream. Allergic reactions can take 12 to 24 hours after contact with the allergen to manifest themselves. It is important in determining the cause of such allergic skin reactions by reviewing events 12 to 24 hours prior. Meanwhile, treatment may require a few hours to several months before relief and elimination of the allergic skin reaction takes place.

Allergic Skin Reactions

Allergic skin reactions occur whenever a dog comes into direct contact with an allergen.

Such allergens include:

  • Dust
  • House dust mites
  • Fleas
  • Ticks
  • Flea-control products, such as flea shampoos and flea collars
  • Insecticidal shampoos
  • Insecticides
  • Pesticides
  • Cleaning products
  • Household products
  • Mold spores
  • Dander
  • Tree, grass and weed pollens
  • Feathers
  • Food, such as pork, chicken, beef, soy, corn or wheat
  • Prescription drugs
  • Fabrics, especially synthetic fabrics
  • Perfumes
  • Rubber and plastic materials

The veterinarian will conduct certain blood and skin tests to determine if the skin reactions are due to an allergy or another medical condition.

Treatment and Prevention of Skin Allergies

Once it has been determined that a dog has an allergy resulting in an allergic skin reaction, prevention is the best form of treatment. This requires avoiding the known allergen. If the allergen is fleas, then performing a flea prevention problem would be the proper treatment method. Cleaning away dust, especially from the dog’s bedding, is important if the allergen is dust and mold. If the dog is outdoors and is in contact with certain plants that cause an allergic skin reaction, then bathing and applying topical ointments to prevent itching will eliminate the allergic problem as well preventing contact with the particular plant.

Some allergic skin reaction medications include:

  • Antihistamines, such as Benadryl
  • Immune modulating drugs
  • Antibiotics
  • Antifungals
  • Medicated shampoos
  • Fatty acid supplements
  • Sprays containing natural products such as aloe and oatmeal
  • Flea-prevention products
  • Anti-inflammatories
  • Steroids, such as Cortisone

Treating the reaction takes time. Cortisone can take 1 to 2 weeks to work on the itchy problem site. Antibiotics can take from several weeks to several months for it to treat the bacterial infection. Allergy shots are given once every few weeks several times a year to eliminate the reaction all together.