Know Your Skin Type

The skin and its appendages make up the first line of defence against factors and threats coming from the outside. Consequently, its functions are an effective barrier and an endocrine and immune system, maintaining homeostasis, excretion, body limit, and metabolism. It is important to know your skin type.

Knowledge of your skin type is of utmost importance when choosing appropriate self-treatment cosmetic products or clinical evaluation for robust data-based decision making. Furthermore, studies show that individuals incorrectly self-assess their skin type.

The use of inappropriate products can lead to skin disorders and disappoint your expectations. The knowledge of the skin type is also important before performing any medical or cosmetic procedures since it can be used to select the most appropriate procedure and to predict and avoid skin reactions and post-procedure complications. A careful and correct classification of the skin type is also relevant because there are several skin types, and they are not static, so it is important to re-evaluate the skin type over the years.

Multiple ethnicity and globalisation give rise to varied human skin types with their particular and complex needs. The response to these needs must be as targeted as possible and the cosmetics market is also following this evolution. Not knowing the type of skin and its characteristics can lead to wrong results with several consequences ranging from changes in the skin physiology to serious adverse effects in aesthetic procedures.

Different criteria are commonly used to classify skin type and skin aging according to the stratum corneum moisture content, type of hydrolipidic film, sun reaction, pigmentation and skin colour, sensitivity, and presence of skin aging signs such as wrinkles, depigmentation, uneven texture, and lack of elasticity.

There is a wide variety of methods to classify skin types that evaluate different skin parameters such as non-invasive instrumental methods (bioengineering tools), visual and tactile methods, and other methods such as instruments (visual rating scales and self-report instruments).

Skin type can be classified according to different criteria such as the stratum corneum hydration, the type of hydrolipidic film, sun reaction, pigmentation and skin colour, sensitivity, and skin aging signs:

• Stratum corneum hydration: a stratum corneum with a water content of around 10% has optimal hydration and consequently the skin is resistant, supple, luminous, soft, and smooth. When the water content is lower, the skin has a rough appearance, lacks flexibility, and may present flaking and dehydration lines.

• Hydrolipidic film: is made up of a mixture of sweat and sebum. It varies from individual to individual depending on its qualitative and quantitative composition, so the proportion of the aqueous and lipid phases will influence the skin type. Sebum production varies with age, gender, and topographical variations of the skin. Oily skin has a more lipophilic hydrolipidic film because of greater sebum secretion. Skin tightness after washing, pore size and number, daily oiliness, and makeup maintenance are all factors to characterize skin as oily or dry'

• Sun reaction: depends on the sensitivity to the sun, tanning ability, and the frequency of appearance of solar erythema, and these characteristics will help determine the phototype.

• Skin colour: is the combination of melanin (yellowish-brown colour) and Hemoglobin (red colour). Skin colour is determined genetically and has to do with the melanin distribution on the epidermis. However, skin colour may also be the result of environmental factors such as sun exposure and hormonal factors that lead to an increase in the amount of melanin on the epidermis.

• Sensitivity: reflects the appearance of unpleasant sensations such as stinging, burning, pain, pruritus, and tingling, accompanied or not by erythema, due to a stimulus, which in normal skin would not cause these sensations.

• Skin aging signs: wrinkles, uneven pigmentation and texture, and lack of elasticity.

Visual methods involve observing the individual’s skin and evaluating its appearance, texture, and possible abnormalities (wrinkles, comedones, acne, flaking, redness, rosacea, pigmentation spots). Tactile methods can be used to evaluate the texture, thickness, temperature, elasticity, and firmness of the skin and the presence of stretch marks. These methods are subjective and dependent on the evaluator’s experience. Together, these methods categorize the skin into its traditional types:

• Normal skin: Visually, looks uniform, luminous, without excessive shine, and has a smooth and even texture without apparent pores. In a tactile examination, the skin appears fresh and smooth, with normal thickness, hydrated, firm, and flexible.

• Dry skin: On visual examination, looks clear, dull (sebum deficiency), and sometimes flaky. It has no visible pores and may have eczematous, reddish areas and rosacea. On tactile examination, the skin appears cold, thin, rough, with little flexibility, and often with dehydration streaks.

• Oily skin: has a shiny appearance, uneven texture with very large pores. It may have comedones and pimples, acne scars, and skin irritations. On tactile examination, the skin is oily, smooth, hyper-seborrheic, and thick.

• Sensitive skin: Visually, shows seborrheic dermatitis, signs of rosacea, scaling, blisters, edemas, redness, and dryness. It can appear hot and rough.

• Aging skin: Exhibits a pale and dull appearance, uneven texture, presence of wrinkles, enlarged pores, and comedones and dyschromic spots. Upon tactile examination, the skin appears cold, thin, dry, rough, and inelastic.

The Fitzpatrick skin types, based on colour:

Type I	Pale white skin, always burns, never tans
Type II	White skin, burns easily, minimal tan
Type III	Medium white skin, sometimes burns, tans slowly
Type IV	Moderate brown skin, burns minimally, tans easily
Type V	Brown skin, rarely burns
Type VI	Dark brown skin, never burns

In Roberts Skin Type Classification System four skin characteristics are evaluated: phototype, photoaging, hyperpigmentation, and scarring ability (scar morphology). Thus, it involves four classification systems summarizing a final total score:

• Fitzpatrick Phototype Scale: a 6-point scale based on skins’ reaction to sun exposure (type I to VI);

• Glogau Scale: A 4-point scale that classifies photoaging skin degree based on wrinkles’ skin examination (type I to IV);

• Roberts Hyperpigmentation Scale: A 7-point scale that determines the post-inflammatory pigmentation and the probability to acquire a pigmentation problem (type 0—hypopigmentation; type I—minimal and transient hyperpigmentation; type II—minimal and permanent hyperpigmentation; type III—moderate and transient hyperpigmentation; type IV—moderate and permanent hyperpigmentation; type V—severe and transient hyperpigmentation; type VI—severe and permanent hyperpigmentation);

• Roberts Scarring Scale: A 6-point scale that identifies the patterns of scarring, by evaluating how the individual’s skin reacts to injury and inflammations (type 0—atrophy; type I—no scar; type II—macule; type III—plaque; type IV—keloid; type V—keloidal nodule).

  
  

This classification system can be used on individuals of any skin colour and is useful in professional practice since it can predict the skin’s response to injury and inflammation after aesthetic procedures or due to post-procedure complications, supporting the treatment strategy. The Roberts Skin Type Classification System helps to select and plan medical and cosmetic procedures and the appropriate treatment products, allows for managing wound care and skin repair, and determines the short and long-term effects of these treatments and procedures.

A careful and correct skin type classification is relevant because it helps select the most appropriate cosmetic products. Knowing your skin type is also important before having any medical or cosmetic procedures to select the most appropriate practice and predict and avoid skin reactions and post-procedure complications.

There is a wide variety of methods to classify skin types that evaluate different skin parameters such as non-invasive instrumental methods (bioengineering tools), visual and tactile methods, artificial intelligence-based analysis and more subjective methods such as instruments (visual rating scales and self-reported instruments). Although subjective, self-reported instruments can collect insight from individuals that cannot be obtained with objective measurements and can also provide information on past events thus supporting more personalised advice. Visual rating scales are also an invaluable resource to assess skin type and aging holistically. The usefulness of these instruments is however dependent on their psychometric validity. Some of the proposed instruments, however, have been poorly validated or not validated at all.

This is not my own work. The above is taken from:

Oliveira, R.; Ferreira, J.; Azevedo, L.F.; Almeida, I.F. An Overview of Methods to Characterize Skin Type: Focus on Visual Rating Scales and Self-Report Instruments. Cosmetics 2023, 10, 14. https://doi.org/10.3390/cosmetics10010014