Before you jump into the causes, we should probably few definite with TEWL is. No, it is not the things we used to fix our appliances. TEWL is an acronym that means Transepidermal Water Loss from the stratum corneum. The term TEWL (TWL or Transepidermal Water Loss) is associated with dermatology that is connected to science. It can be defined as the quantification of the water loss as it passes through the epidermal layer (skin) as it is diffused or evaporated into the surrounding atmosphere. It is one of the processes in humans of which we have not much physiological control. In other words, TEWL is known as an “insensible water loss.”
To identify skin damage caused by certain chemicals, physical insults or pathological conditions, TEWL measurement is useful. Physical insults include “tape stripping” while pathological conditions include eczema. The variations in the rate of TEWL will be indicative of the levels of damage caused to the skin. That said, there are environmental factors that affect TEWL:
- Environmental Humidity Levels
- Cold Temperature Influx
- Time of Year (Season)
- Skin Moisture Content (Hydration Level)
Due to these variations, it is not a perfect application of measurement. Extract care must be taken while interpreting the rates of TEWL.
The stratum corneum is the outermost lay of the epidermis. It consists of corneocytes or dead skin cells. It is made up of 15 to 20 layers of fattened cells containing no cell organelles or nucluei. They are imbedded in the lipid matrix and show filamentous keratin in their cytoplasm. They stand to form a protective barrier to sub-tissues. It’s primary function is the prevention of infection, dehydration and stress caused by chemicals. From beginning to end, the shedding and renewal processes takes approximately 14 days.
Effects of TEWL In the Skin
Transepidermal Water Loss is an evaporation of water from the stratum corneum. There are numerous external factors that cause TEWL. The loss of moisture is the primary factor linked to the development of dry, scaly skin as well as irritant dermatitis.
The stratum corneum receives water from the dermis and the environment. The water content in this outermost layer of skin can fluctuate with the humidity. Dry skin will be accentuated with prolonged exposure to low humidity, wind and cold.
External factors such as damage caused to the stratum corneum barrier can occur by the denaturion of keratin protein. This removes natural moisturizing factors. It also interrupts the lipid bilayers. Factors that cause this damage include:
- Excessive Use of Water/Soap
- Irritating Chemicals
Cleansers have been designed for removing unwanted materials form the skin. This includes dirt, oils and sebum. The drawback from this is that the harshness of these chemicals can cause damage to the stratum corneum. This leads to an increase in environmentally sourced irritation and sensitivity susceptibility. This also reduces skin moisture and smoothness, a primary concern of women seeking a youthful complexion. This can lead to wrinkles and fine lines forming on the surface of the skin.