In simple terms, atopic means 'allergic', and dermatitis means 'inflammation of the skin'. Put the two together, and you have atopic dermatitis (AD), a chronic itchy skin disease which can affect both dogs and humans alike. It occurs when the immune system reacts abnormally to allergens in the environment, causing symptoms such as:
 

• Itching (you may see your dog scratching, rubbing, chewing or biting itself excessively)
• Scratch marks (caused by the above)
• Redness (which may or may not be caused by scratching etc.)
• Discolouration of the skin (known as hyperpigmentation)
• Skin thickening (known as lichenification)
• Self-induced hair loss (known as alopecia)

Atopic dermatitis can be limited to a few areas of the body or widespread over the dog's body, usually the face, feet, ears, folds, friction and flexure areas.*
 

Atopic dermatitis is a recurrent disease that usually requires lifelong therapy. It is difficult to treat, as many of the traditional treatments are only partly effective and may be associated with side effects.
 

*Friction sites are the areas that come in contact with the ground. Flexure points are the patches of skin covering the bent portions of the joints.