Current Definition of Skin Types and Influencing Factors
The cosmetic approach to dermatological consultation is based on an assessment of the physiological condition of the skin that takes subjective and objective considerations into account. The skin is currently divided into four different types or conditions:
Where normal, physiological conditions are present, the skin is described as eudermic: The skin is fine pored, well supplied with blood, has a rosy colour and uniform transparency. It is neither too oily nor too dry and, from an objective point of view, free from problems. The skin condition can be considerably altered by endogenous and exogenous factors.
Scaling patches on the skin can cause intense itching and a feeling of tightness. The skin appears rough and blotchy, sometimes even prematurely aged.
Characterized by enlarged pores filled with comedones (blackheads), oily skin shines, has irregular transparency and often looks pale and yellowish.
The forehead, chin and nose are oily, while the cheeks appear normal to dry.
Internal and external factors influencing the skin condition
Internal (endogenous) factors include a predisposition to one of the above skin types or to certain skin diseases such as atopic dermatitis (neurodermatitis), psoriasis or ichthyosis.
Unlike premature skin aging, which is caused by external factors, biological endogenous skin aging is genetically determined and characterized by:
- Diminishing capacity for cell regeneration and renewal
- Reduced sebaceous and sweat gland secretions
- Hardening of the connective tissue with reduced water binding capacity
- Degeneration of elastic fibres
Predisposed people can react to mental and stress-induced triggers with pathological skin conditions. Hormones can also have a physiological and pathological effect on the skin condition. For example, hormonal changes trigger the acne of puberty or the age-related atrophy of the skin beginning with menopause. Diseases of endocrine glands (i) such as the adrenals are often associated with changes in the skin condition.
The external, environmental factors include:
- Formation of free radicals (i), especially due to UV exposure, smoking, toxic stimulants like alcohol
- Exposure to aggressive substances like alkalis
- Air temperature and humidity
UV radiation, pollutants, medicines, toxic stimulants, ozone and certain foods cause formation of the highly reactive free radicals (i). These are responsible for oxidation processes in body tissues resulting in damage to the cell interior and membrane. In the epidermis, free radicals (i) are generated mainly by UV exposure. Years of unprotected sun exposure leads to chronic light-induced damage and with it premature skin aging.
Regular use of moisturizing and cleansing products with a neutral or alkaline pH (i) overtaxes the natural base neutralizing capability of the skin and makes it susceptible to eczema and skin infections. Because sebaceous gland activity in small children and the elderly is not yet fully developed or diminished, there is a physiological reduction in the skin’s buffer capacity.
Many people such as hairdressers, masons and industrial workers come into contact with the most varied types of noxae (i) on the job. Here especially acids, alkalis and solvents play a role. Also various surface-active agents (surfactants (i)) like sodium lauryl sulphate can cause damage to the horny cell structures and impair the permeability barrier (i) in the horny layer. As a result, the skin can dry out even to the point where it develops eczema.
Showering too frequently and too long with hot water leads to a loss of the skin’s natural moisturizing factors (i) (NMF) as well as its surface lipids. The skin dries out and becomes rough. The skin reacts to the cold at first by narrowing of the skin’s blood vessels to protect the body from losing too much heat. Sustained cold temperatures reduce sebaceous gland secretion (i) and dry out the skin.
In a sauna or centrally-heated rooms the sweat glands (i) produce more sweat, which quickly evaporates due to the heat or dry air. The skin dries out.
If exposure to the exogenous factors listed in the table is only temporary, the skin’s protective mechanisms are able to more or less cope with the irritation. If exposure is too long, the skin’s protective mechanisms fail. The skin is no longer normal and healthy but sensitive and prone to disease.