Why Is My Dog Itchy?

We sometimes talk about intolerances and allergies like this is the only thing that can cause your cat or dog’s itching. There can be so many reasons, layered reasons and some more serious than others.

Here we explore some of the undetected and misdiagnosed reasons for your dog being itchy.

Adrenal function

The adrenal glands are located just in front of the kidneys.  You will recognise them from when we discuss the stress response more often than not.

The adrenal gland has 2 parts—the cortex and the medulla.

The adrenal cortex is subdivided into 3 layers, and each layer produces a different set of steroid hormones. The outer layer produces the mineralocorticoids, which help regulate sodium and potassium salts. The middle layer produces glucocorticoids, which are involved in metabolising nutrients and reducing inflammation and immune responses.  Finally, the inner layer produces sex hormones such as oestrogen, progesterone, and androgens.

The adrenal medulla plays an important role in response to stress or low blood sugar levels in the body.  It releases adrenaline and noradrenaline, both of which increase heart rate and blood pressure, increase blood sugar and slow digestion; the hallmark responses when us or our dogs are exposed to a stress trigger.

The adrenal glands are part of the endocrine system – which is simply a system of glands that release chemical messengers called hormones.  The endocrine system influences almost every cell, organ, and function in the body.

So, if there is any issue in any part of it, things can start to go wrong.

The two most common ways in which adrenal glands cause health issues are by producing too little or too much of certain hormones, which leads to hormonal imbalances.

Hyperadrenocorticism (Cushing’s Disease) due to an excess of cortisol production frequently causes dogs to itch, lose hair, have thin skin with dark pigment, drink excessively and have recurring skin problems.

But this raises another point, even if there are no physiological issues with the adrenal glands, high cortisol levels due to daily stress can also lead to itchy skin!

Thyroid Function

We’ll continue with the hormones for a minute and look at thyroid function.

The thyroid is a butterfly shaped gland found in the neck.  One of its main functions is to produce hormones to regulate the body’s metabolism, the process that turns food into energy.

This too can produce too many hormones, or too few.  These conditions are known as hyperthyroidism and hypothyroidism respectively.



Hyperthyroidism in Cats

Skin issues are regularly noted in times of thyroid dysfunction, and this includes itchiness.

Kidney Function

Intense itchiness often accompanies late-stage kidney disease, and whilst the jury is out on the exact reasons behind it, it is thought that it’s relating to the build up of toxins in the body.

This leads us nicely into the same itchy symptoms associated with early-stage liver disease, and this is considered for similar reasons.


Detoxification is carried out by a range of mechanisms, and this comes in particularly handy if one pathway is overwhelmed, another can pick up the slack.

The Liver

The liver neutralises a range of toxic chemicals, both those produced internally (waste from used hormones or neurotransmitters for example) and those from the environment, like air pollution, pesticides, and food additives.

It does this by filtering the blood to remove large toxins, synthesising, and secreting bile and lastly enzymatically disassembling unwanted chemicals found in the body.

Enzymatic Detoxification

This enzymatical detoxification occurs

in three phases.

Phase I directly neutralises chemicals and changes them into new metabolites.  These are then processed by phase II enzymes.  This is known as the conjugation phase, which in short, liver enzymes attach small chemicals to the toxin.  There are many ways in which this is done, it all depends on the type of chemical the liver is trying to manage.

Phase I results in high levels of reactive oxygen species so antioxidant levels are key in modulating potential damage.

Phase II is nutrient demanding and sufficient levels of key vitamins and minerals like vitamin A, C, E, B1, B2, B3 and iron are essential.

Phase III is the elimination phase. For optimal excretion of toxins through the digestive system, gut health is vitally important.  Maintaining the mucosal barrier is key for gut health along with supporting motility.

The kidneys will also filter and process toxins from circulation, excreting them as urine.

The skin also forms as an elimination pathway.  This is why detoxification issues can result in skin issues.  In cases of liver disease, it is considered that bile salt deposits under the skin, which results in itchiness.

The most important thing to do to support detoxification is to avoid exposure in the first place, so consider how much you and your dog are exposed to:

  • Pesticides
  • Heavy smoke
  • Phthalates
  • Mould
  • Medications like steroids, antibiotics, and painkillers
  • Heavy metals
  • Cleaning products
  • Air fresheners
  • Eating foods cooked at high temperatures (most commercial dry foods)

This list is not exhaustive, but it is a place to start.

This mechanism also applies to vaccines.

There is increasing evidence that over-vaccination is associated with the development or aggravation of immune-mediated disorders and chronic diseases in individual pets that are genetically predisposed.

The primary role of the immune system in dogs is to protect against foreign invaders, or abnormal cells that invade or attack.  The immune system must distinguish between self and non-self.  Substances that stimulate a response are antigens.  These can be contained within bacteria, viruses or microorganisms or cancer cells.  They may also exist on their own, like pollen or food particles.  There are three lines of defence, physical barriers, nonspecific immunity, and specific immunity.

But the immune system does not always function properly, it can be underactive and overactive.  An underactive system puts the animal at risk of infection, but an overactive immune system can attack parts of its body that it misidentifies as being foreign.  This is what happens in autoimmune conditions.  The immune system can also overreact and produce too many antibodies or other chemicals; these are what we see as hypersensitivity or allergic reactions.  And often what leads to itchy skin.


Nutritional Deficiencies

At first glance it’s easy to consider that certain nutrient deficiencies may lead to compromised skin function, and therefore lead to an inflammatory skin condition and subsequent itching, but nutrient deficiencies are indicated in many health issues, and as we have already explored, many health issues can lead to itchy skin.

There are of course nutrients key to skin health:

Top Tips For Skin Health

Tackling Atopic Dermatitis

and essential nutrients for kidney and liver health:

Nutrients for Kidney Health

Foods to Feed in Liver Disease

But there are other causes of itching like pain and spinal issues.

Dogs In Pain

There is such a thing as a neuropathic itch which is a symptom of nerve malfunction.

Toxins, medication side effects, and vitamin deficiencies frequently damage the peripheral nervous system.

Noted Deficiencies:

  • Vitamin B12
  • Copper
  • Vitamin E
  • Vitamin B6

Why Your Dog Needs B12

Does My Dog Have a Vitamin Deficiency

Why Does My Dog Need Minerals – Part One

Why Does My Dog Need Minerals – Part Two

Another note to make is that certain antimicrobial medications are associated with peripheral neuropathy and therefore neuropathic itch.

Findings Here

It is also apparent that there may be a genetic predisposition to many of the above-mentioned health issues.  In addition, certain genes are responsible for optimal skin function.

Can Genes Result in Poor Skin Function


Can you see how hard it is to even scratch the surface of an itchy dog?  When we consult with an itchy dog, we collate as much information as possible to establish what may bubbling under the skin.  We don’t have a magic wand, but we do have decades of clinical experience on which to draw.

If you would like our support, then check out our services below.

Thanks for reading,

Team MPN x  

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