This is what a demodex mite looks like magnified by 1000 under the microscope
A tiny creature created huge problems for Crystal.
Crystal is a 1 year old Chihuahua cross who was rescued from the pound by her loving owners despite the fact that she was scratching and missing patches of hair. After trying many shampoos with no improvement, Crystal was brought into VetHQ.
On examination, Crystal didn’t appear to have any fleas but had greasy, scaly, smelly skin. We took multiple skin samples to determine whether her hair loss and skin disease was due to bacteria, fungi, mites, allergies or another medical issue. This involved plucking some hair, scraping the skin with a blade and using sticky tape to pick up skin cells. We looked at the samples under the microscope and diagnosed Crystal with Demodecosis (infection caused by Demodex mites).
Crystal is a 1 year old Chihuahua cross who was rescued from the pound by her loving owners despite the fact that she was scratching and missing patches of hair. After trying many shampoos with no improvement, Crystal was brought into VetHQ.
Demodex are microscopic mites that live in the deep hair follicles. While they are normal residents of skin in small numbers, they become a problem when they overpopulate. Bitches can transmit the mites to their puppies during nursing. In adult dogs they are not contagious and overpopulation is associated with dysfunction of the immune system (due to other diseases, poor nutrition, stress, medications such as corticosteroids), allowing the mites to increase in number. There is also a strong genetic influence and breeds predisposed include Shar Pei’s, Bulldogs, Staffies, Shih tzus and Pugs. The disease is not transferable to humans.
The clinical signs are generally hair loss, redness, thickening, hyperpigmentation and scaling/crusting of the skin with or without itchiness. Areas of hair loss are most likely on the dog’s trunk, face or feet.
Diagnosis is made by scraping the skin with a scalpel blade to obtain a sample from the deep hair follicles where the mites live. Most dogs are not bothered by the scraping. We look at the sample under the microscope to see if we can find any demodex mites.
This video was taken looking down the microscope onto a scraping sample from Crystal’s skin. It shows a live mite moving.
In most cases, long term treatment is required (minimum of 2.5 months) and if there is an underlying disease which predisposed to demodecosis we need to treat that too. The main reason for treatment failure is premature cessation of medication.
Crystal probably got the mites as a puppy from her mum. We have started her on weekly Malaseb shampoo washes to flush out the hair follicles where the mites are living, a 3 week course of antibiotics to clear the bacterial skin infection caused by her scratching and a medication which affects the mites’ nervous system, paralysing them and causing their death.
We are very hopeful that with this treatment, Crystal will make a full recovery and grow all her hair back.