Demodex Mange

• Demodectic mange is also known as red mange. It is caused by the demodex mite. This mite lives on nearly every dog and is normally harmless, but in some breeds such as Yorkshire terriers, the mite can cause severe itching, crusty or red skin and hair loss. Demodectic mange can be treated using a medicated dip.
  
  

Sarcoptic Mange

• Yorkies can also be affected by sarcoptic mange, or scabies. This type of mange is caused by the Sarcoptes scabiei mite, which burrows under the dog's skin to lay its eggs. This causes extreme itching and hair loss. The infestation can be treated with a drug called Ivermectin.
  
  

Environmental Allergies

• Yorkshire terriers can become allergic to external substances such as carpet cleaners, laundry detergent, or certain types of shampoo. These allergies can cause severe itching and fur loss. The treatment for external allergies is to determine what is causing the allergy by using a process of elimination.