Posted : 02/01/2002

Posted : 02/01/2002

Skin Type/Subtype:
Another Proposed Method To Classifying The Skin

by Patricia Reykdal and Donald L. Smith

Professional tanning salon operators provide their customers with a dose of ultraviolet radiation that is optimal for each tanning session. The goal is neither to overexpose nor underexpose your clients.

The problem with existing exposure schedule guidelines posted on tanning units is that clients, especially those with higher Skin Types/Subtypes, significantly would be underexposed to UVR if the guidelines were followed.

The following article presents an alternative method of classifying the skin, which has been proposed to the U.S Food and Drug Administration for its approval. Many salons nationwide have been using this method for more than two years. Review the material so you can easily explain the concept to your employees and customers. Additionally, there is a questionnaire available at www.lookingfit.com that you can download and use in your salon.

Understanding The Skin

Mother Nature has provided us with three separate ways to avoid overexposure to ultraviolet radiation (UVR). Overexposure is defined as a dose of UVR sufficient to cause a sunburn that can damage our DNA. On the other hand, exposure is defined as a dose of UVR below the level necessary to cause a sunburn.

Our three natural ways of preventing sunburn are constitutive pigmentation, facultative pigmentation and sunburning.

Constitutive Pigmentation

Our constitutive pigmentation is our natural skin color and it is based upon our genetic heritage. As a rule of thumb, the darker our natural skin color, the greater is our protection from overexposure to UVR and it provides our only permanent means of photoprotection.

Individuals who are Skin Type 0s (albinos) and Skin Type 1s (the most-sensitive Caucasians) have the highest relative risk of sunburning.

Facultative Pigmentation

Our facultative pigmentation--better known as a "tan"--is our level of acquired or adaptive photoprotection to UVR. This method of protection from UVR is transitory since a tan can, and usually does, darken or fade over time and season of year.

Adaptive pigmentation provides the natural equivalent of SPF 3 to SPF 5 protection from the sun. Skin Type 0s have no photoprotective constitutive pigmentation, and Skin Type 1s, who have minimal levels of natural skin color, are genetically incapable of developing adaptive pigmentation. These individuals must wage a life-long battle against the sunburning power of UVR utilizing sun avoidance, protective clothing and sunscreens.

Sunburning

The sometimes painful process of sunburning is the third natural way we have to protect our DNA from damage. The redness and swelling associated with a sunburn all serve to protect us from further acute damage to UVR and is Mother Nature's way of letting us know that we haven't been very smart.

Before discussing how to determine your clients' Skin Type/Subtype, it is essential to know the reasons why it makes sense to know their Skin Type and their Subtype. The graph on page 138 shows the time it will take to sunburn for the various Skin Types/Subtypes in the sunlight experienced by much of the country at noon on a typical summer day (6 UV Index unit reading). For this example, it is assumed that no base level (facultative pigmentation) of tan exists.

As you can see, a Skin Subtype 2A has 21 minutes until they will accumulate 1 MED (minimal erythemal dose of ultraviolet radiation) which is the level at which they will experience a sunburn. A Skin Subtype 3A, on the other hand, can tolerate double this amount--42 minutes--before suffering a sunburn. A Skin Type 5 (brown-skinned individuals) can tolerate 72 minutes of exposure to sunlight without sunburning, while a Skin Type 6 (black-skinned individuals) can tolerate 84 minutes.

Therefore, the above graph shows very clearly why it is necessary to know your clients' Skin Type and their Subtype in order to accurately predict the time it will take them to sunburn. Thus, you can see that tolerance to UVR is Skin Type/Subtype dependent. The darker the natural skin color, the greater the tolerance to UVR.

If you are familiar with Skin Typing but not Subtyping, you can readily see from the chart the reason why Subtyping is necessary in order to prevent sunburning. For instance, if you look at the mid-point of the Skin Type 2 segment of the population (Skin Subtype 2Bs), you will see that it takes 28 minutes to sunburn. If you applied that tolerance level to Skin Subtype 2A individuals who have a tolerance of 21 minutes, you can see that 2As would be exposed to seven minutes of UVR more than can be tolerated by these sun-sensitive people. This additional time is more than sufficient to cause a sunburn.

Moreover, if a Skin Subtype 2A individual would base their calculation time for protection by a sunscreen on the tolerance level of a Skin Subtype 2B, the seven-minute error is multiplied by the protection factor. For example, if a sunscreen with an SPF 8 is applied, a Skin Subtype 2B would have 224 minutes (8 x 28 minutes) of protection, while a Skin Subtype 2A would have only 168 minutes (8 x 21 minutes). The difference of 56 unprotected minutes is more than enough to cause a painful sunburn.

It should be kept in mind that people must apply the proper dose of sunscreen in order to obtain the rated protection. It takes 1.25 ounces--a full handful--of lotion for a full body application on an adult. If a person only uses one half as much as they should, they will cut down the protection by 50 percent; therefore, an SPF 8 becomes an SPF 4 sunscreen. In addition, a person should reapply the lotion every hour and every time they get wet in order to be fully protected.

The Skin Typing/Subtyping questionnaire will allow you to calculate your clients' Skin Type/Subtype. Since a person's natural skin color doesn't change, they can use this value for the rest of their lives.