The term pH (potential of hydrogen) was introduced in 1909 by Danish biochemist Soren Sorensen.
It denotes a measure of the degree of acidity of aqueous solutions , that is, the potential of hydrogen.
Acidity and alkalinity are measured on a scale of 1 to 14.

• pH 1 indicates a strong acid.
• pH 7 a neutral solution.
• pH 14 a strong base.

Adequate skin pH is the range in which the skin provides the best protection for the body.
Too low a pH will result in excessive sebum production.
Too high a pH will lead to dry skin and excessive growth of bacterial flora.
Therefore, bathing your dog or cat in human shampoo (even recommended for infants or allergy sufferers) can damage the epidermal barrier.

Translated with DeepL.com (free version)

The skin consists of three layers: epidermis, dermis and subcutaneous tissue.

1. epidermis

The epidermis is the outermost layer of the skin in direct contact with the external environment.

It is made up of four layers:

cells of the basal layer, which give rise to the next layers. In this layer are melanocytes, so-called pigment cells. The melanin they produce provides a protective barrier against UV radiation and captures free radicals.
The cells of the squamous layer, which are connected by desmosomes. This is where the most intensive production of keratin, the protein that is the basic building block of hair, takes place. Here there are also dendritic cells, the so-called «scout cells», whose protrusions penetrate between keratinocytes recognize antigens (i.e. «strangers») and transmit this information to further cells of the immune system. They constitute the first immune barrier.
granular layer cells containing keratohyaline granules having a direct relationship with the maintenance of a proper water barrier (when there are too few of them, excessive water loss and penetration of pathogens occurs).
cells of the stratum corneum made up of dead, nucleated corneocyte formations. Compared to the human epidermis, the stratum corneum in the dog is very thin.

The process of epidermal renewal (keratinization) takes about 21 days.
Regular exfoliation of the epidermis is one of the mechanisms that constitute the epidermal barrier.

2. dermis

In the dermis are located the hair follicles, blood vessels, nerves, glands and the hair stroma muscle. This layer owes its elasticity to its collagen and elastin content.

3. subcutaneous tissue

The deepest layer of the skin is the subcutaneous tissue.
It is made up of connective tissue fibers and fat cells, thanks to which it owes its heat-insulating function.

PRZEKRÓJ SKÓRY I WŁOSA PSA.
Prawa do grafiki — Laboratorium Dermapharm sp. z o.o.

Unlike humans, the skin of dogs and cats, for the most part, is covered with hair. Depending on the breed, dogs vary in hair coat.
The lifespan of hair is genetically programmed. The hair’s growth phase is anagen, the slow death phase is catagen and the resting phase, or telogen, when the hair is waiting to fall out. Thus, hair loss is a physiological phenomenon. Regular brushing not only improves the emotional bond with your pet, but massages his skin improving circulation in it, and most importantly removes dead hair.
However, a feature that differs between a dog’s hair and ours is the fact that a single hair follicle of a dog contains a longer hair (the coat) and several shorter hairs (the undercoat). In practice, in the case of an infection involving a single hair follicle (such as in the course of inflammation or erysipelas), there is a loss of many hairs, which manifests as extensive baldness.
The predominant part of the hair structure is a protein — keratin. Resistance to mechanical factors, hair keratin owes primarily to sulfur amino acids (cystine, methionine). Therefore, the key to healthy skin and hair coat is not only proper care , but proper nutrition.

It is worth taking care of dietary supplementation with preparations containing:

1. EFAs (polyunsaturated fatty acids), which include:

omega 6 acids (are involved in maintaining the normal water barrier of the skin, a good source of them is borage oil)
omega 3 fatty acids (have anti-inflammatory and anti-edema effects, high content is in fish oil).Note! It is very important to maintain the so-called «Golden Ratio», that is, the appropriate ratio between omega 3 and omega 6 fatty acids as 1:5, so a reasonable and convenient solution is to buy a ready-made preparation

2. zinc, which affects the rate of cell division and participates in the process of wound healing

3. biotin (belongs to the group of B vitamins) — when ingested, it goes to the sebaceous glands, having an inhibitory effect on oily skin.

An important role as a protective barrier for the skin, is sebum, the secretion produced by the sebaceous glands. These glands are located on the surface of the hairy skin. Thanks to sebum, proper hydration of the epidermis is maintained (it acts as a water-lipid mantle) and protects the hair from soaking up water. Sebum acts as a barrier against the entry of pathogens from the outside.

As for the grooming bath, its frequency should depend on the dog’s age, breed, activity, lifestyle and location.
Dogs of certain breeds, such as yorkshire terriers, shih tzu or Maltese, due to the structure of the coat, require more frequent baths. It is worth remembering that for all breeds, the basis for maintaining good hair condition is regular brushing. This helps remove dead hair, additionally building a bond with the animal.
In summary — except for certain breeds, bathing a dog should be done no more often than every 3-6 months.
In the case of puppies, bathing should take place only if necessary and not before the completion of a full vaccination calendar.
It is also important to remember to choose a shampoo with the correct pH, that is, use a product designed for dogs.
It is also important to dilute the shampoo with water in the ratio of 2 parts water and 1 part shampoo.
When bathing, care should be taken to ensure that the water does not flood the external ear canals and eyes (we exclude the head from the bath).
Especially in the autumn and winter, care should be taken to ensure that bathing does not contribute to the development of an infection, so it is advisable to perform this activity after the last walk.
Since bathing is generally not a pleasant experience for our pet, let’s not forget about motivation, i.e. reward.

A healthy cat by nature is a cleaner and, apart from regular brushing, does not require additional coat care.
In addition, due to the «feline personality», bathing in the case of a cat is associated with great stress.
In the case of a therapeutic bath, it is important to remember that, due to the method of toileting, no chemicals or fragrances must be left on the hair.

lek. wet. Ilona Blanc, Specjalista Chorób Psów i Kotów