Dry, itchy skin PDF Print E-mail
News - Rubrieke
Tuesday, 29 July 2014 07:18
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Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .


Dr Liesel van der Merwe

Winter is here and with it dry, flaky skin.

The epidermis is the outer cellular layer of the skin. The layer underneath is called the dermis and contains blood supply, nerves and fatty and connective tissue. The epidermis is composed of four or five layers of cell types, depending on the region.

The deepest layer is the germinal layer of cells from which all the cells originate. As new cells are formed older ones “grow” outwards and form the stratum corneum. This is the most superficial layer of the skin and is made up of 10 to 30 layers of cells.

The cells are flattened and fit together like bricks, each encapsulated by water-retaining keratin and ceramide proteins. The cells are held tightly together by a skeleton of protein junctions. In-between the cell layers are multiple stacked lipid layers. The stratum corneum plays a vital role in the skin’s barrier function.

The tight cell structure and skeleton makes a physical barrier, the lipids and other proteins make a chemical barrier and immune surveillance cells an immune barrier. The multiple layers of lipids prevent trans-epidermal water loss. The skin’s ability to hold water is due to the stratum corneum and is critical for maintaining a healthy skin. Beside disease processes, shifts in humidity may alter the hydration status of the stratum corneum, which will decrease its barrier function.

Animals with allergic skin disease have a dysfunctional skin barrier. There is a chicken-and-egg scenario here because some dysfunction is secondary, but there is an underlying weakness in the skin barrier in allergic dogs as a primary problem. 

Both lipid and protein skeleton abnormalities have been described, which lead to a weakened barrier, allowing allergens and bacteria access to the deeper layers of the skin where they can cause a systemic response.

In winter our skin naturally dries out due to the decrease in humidity. If an animal has some skin barrier deficiencies, this effect will be exaggerated. Dry skin is itchy, so your dogs will scratch more, and creams and ointments might not work because pets lick them off.

Excessive bathing and use of shampoos, unless medically indicated, may worsen a dry, itchy skin as you keep removing the superficial oily layer.

A systemic approach is to try and improve the lipid quality and increase the health of the skin cells. This we can do by supplementing with Omega-3 fatty acids, contained in cold water fish, such as salmon, and flax seed. Omega-6 fatty acids are more prevalent in vegetable oils and do not perform the same function. Omega-3 fatty acids are eventually included into the structure of the cell walls, where they decrease the body’s response to inflammation. The ideal ratio Omega-6 to Omega-3 to maintain healthy skin function is 5:1.

Make sure your pet has a good quality diet with sufficient oils and antioxidants to keep those oils from going rancid. Supplements with Omega-3 oils are easily available. Feeding a proper diet with adequate Omega-3 content is more effective than supplementing a poorer diet.

The effect of the Omega-3 supplementation will only be seen after about two months, as it has to be built into the cell structure. This dietary management would need to be continued life-long. There are additional benefits in joint and kidney health.

However, excessive supplementation of Omega-3 will decrease immunity as some inflammation is necessary for the body to fight infections.

Check the skin for any pimples, and red flaky areas, which may indicate an underlying skin infection. Antibacterial shampoos can be used as a trial. The more expensive ones are milder and cause less stripping of the natural oils on the skin. Check for fleas. In allergic dogs even one flea bite can cause itching. Ensure that deworming is up to date.

Most animals with skin problems have underlying problems. If the cause is corrected, such as an underactive thyroid gland, diabetes or Cushing’s disease, you may solve the problem. In many cases the cause is not identifiable and the patient will have a lifelong susceptibility to skin problems. The goal is managing the signs as effectively as possible.

 

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