Skin Care Glossary: Common Terms and Ingredients Explained - Gladskin

Skin Care Glossary: Common Terms and Ingredients Explained

Let’s face it. Skin care is complex, and sometimes even the most common terminology is downright confusing! We want you to be able to make educated decisions about your skin care, and you can only do that when you understand what your dermatologist, primary care provider, or esthetician is saying. Bookmark this page to save for later. We’re covering all the must-know skincare terms so you can better understand the skin microbiome, eczema, rosacea, and acne. 

Skin Microbiome


Endolysins are enzymes produced by the interaction between bacteria and bacteriophages. They can selectively target bacteria by damaging their cell walls and destroying them from the inside.

Incorporate endolysin technology into your skincare routine:



Enzymes are a broad group of proteins created by all living things. They act as catalysts in biological and chemical reactions.



Prebiotics aren't bacteria — but rather compounds that promote the growth or activity of beneficial microorganisms such as bacteria. One way to think about prebiotics: They’re the food that fuels your probiotics.



Probiotics are live bacteria and yeasts that benefit the body. Because of their health benefits, they’re often referred to as “good” or “helpful” bacteria. Probiotics are often found in digestive supplements, fermented foods like kimchi, sauerkraut, and yogurt, and some skincare products.


Learn more about probiotic skin care:


Skin Microbiome

The skin microbiome is the ecosystem of microorganisms, their genes, and their surrounding environments that lives on the surface of your skin.  It’s home to a diverse array of bacteria, mites, viruses, and fungi.


Learn more about the skin microbiome:


Products that support a healthy skin microbiome:



Synbiotics are a mixture of live microorganisms and prebiotic material designed to benefit the health of its host. There are two types of synbiotics: complementary synbiotics, in which a probiotic and prebiotic are combined, but work separately, and synergistic symbiotics, in which probiotics and prebiotics work together. 


Eczema & Dermatitis

Allergic Rhinitis

Allergic rhinitis, also called seasonal allergies or hay fever, cause watery and itchy eyes, sneezing, and runny nose. This allergic response can happen seasonally or year-round. People who experience hay fever are more likely to have eczema. Histamines are compounds released by cells as a result of injury or an allergic/inflammatory reaction.


Atopic Dermatitis 

Atopic dermatitis is the most common form of eczema, appearing as itchy, scaly, dry skin. It tends to begin in childhood and remain chronic throughout a person’s lifetime. While it can be located anywhere, it’s most often found in the creases of your elbows or knees.


Learn more about atopic dermatitis:


Atopic Triad

The atopic triad describes the tendency for eczema, asthma, and allergies to occur together. Most often, the progression of the atopic triad starts with eczema, then food allergies, followed by asthma, and then hay fever (allergic rhinitis). This sequence is called the “atopic march.”


Colloidal Oatmeal

Colloidal oatmeal is ground oat grain. It contains the bran, germ, and endosperm of the oat grain and offers moisturization, anti-inflammatory effects, barrier protection, and soothing properties to those with eczema.


Contact Dermatitis

Contact dermatitis is a type of eczema that creates an itchy rash on the skin as a result of direct contact with an allergen or irritant.


Learn more about contact dermatitis:



Dermatitis is a general term that refers to inflammation of the skin. The most common types of dermatitis include contact dermatitis, seborrheic dermatitis, nummular dermatitis, and atopic dermatitis.


Dyshidrotic Eczema

Dyshidrotic eczema, also sometimes called pompholyx, foot-and-hand eczema, palmoplantar eczema, or vesicular eczema, is a form of eczema that causes blisters on the hands and feet that come and go over extended periods of time.


Learn more about dyshidrotic eczema:



Skin fissures are splits or cracks in the skin. They occur most often in areas of the skin that are dry or calloused, such as the heels of the feet or palms of the hands.



Histamines are compounds released by cells as a result of injury or an allergic/inflammatory reaction. Histamines are compounds released by cells as a result of injury or an allergic/inflammatory reaction.



Lichenification refers to when your skin becomes leathery and thick. The process can occur as a result of excess scratching or rubbing. The area of skin may also become bumpier, darker, or harder than the surrounding skin.


Nummular Eczema

Nummular eczema is a type of eczema that involves itchy, circular rashes on the skin. It can look like psoriasis, ringworm, or even other forms of eczema and is most common on the torso, arms, legs, and hands.


Learn more about nummular eczema:


Occupational Dermatitis 

Occupational dermatitis is a form of contact dermatitis that occurs when you come into contact with an irritating chemical in the workplace.


Learn more about occupational dermatitis:


Perioral Dermatitis 

Perioral dermatitis is inflammation around the mouth. It can be triggered by topical or inhaled steroids as well as heavy moisturizers and cosmetics. It appears as a rash and may be flaky or include bumps that are often mistaken as acne.



Also simply called “itching,” pruritus causes an irritating sensation that creates discomfort and the urge to scratch the skin.


Seborrheic Dermatitis

Also known as dandruff, seborrheic dermatitis is a skin condition that causes scaly, crusty, red patches of skin on oily parts of the body. It’s most often seen on the face, nose, eyebrows, ears, eyelids, armpits, and especially the scalp. In infants, it’s known as cradle cap.


Learn more about seborrheic dermatitis:


Stasis Dermatitis 

Stasis dermatitis is a form of eczema caused by poor circulation in the lower legs. Valves in the veins weaken and leak fluid, which causes water and blood cells to pool in the legs. It’s also referred to as gravitational dermatitis, venous eczema, or venous stasis dermatitis.


Learn more about stasis dermatitis:



Have you ever noticed your eczema oozing clear or straw-colored liquid? That’s “weeping.” When the liquid dries up, it causes a yellow or orange crust to form over your skin. Weeping may be a sign that your eczema has become infected. Weeping can also occur when you have fluid-filled blisters.




Acne Vulgaris

Acne vulgaris is the official term for what you likely think of as the “standard” or “common” type of acne. Acne vulgaris results in pimples that are caused by oil, bacteria, and other impurities that clog the pores on your skin. One of the major culprits behind acne vulgaris is hormonal fluctuations. That’s why it’s especially common during puberty. 


Learn more about acne vulgaris:


Products for acne-prone skin:


Atrophic Scars

Atrophic scars, also called pitted scars, are indented marks on the skin as a result of acne. When this type of scarring occurs, it indicates that the skin was unable to regenerate tissue, so the skin healed below the normal layer of tissue.


Learn more about acne scarring: 



Unlike whiteheads, which are closed skin pores that have become clogged, blackheads are open skin pores or hair follicles clogged with oil, dead skin cells, and bacteria. As the name suggests, they appear on the skin as small black spots in your pores.



The term “comedones” is the technical way to refer to both blackheads and whiteheads. In general, comedones are small white, dark, or flesh-colored bumps.


Cystic Acne

A form of inflammatory acne, cystic acne causes pus-filled pimples that form deep under the skin’s surface. This type of acne is often more painful than acne vulgaris.



A cyst is a fluid-filled growth that can be very painful. Cysts are most often associated with cystic acne, one of the tougher versions of acne to treat.


Hormonal Acne

Hormonal acne can appear as blackheads, whiteheads, or most often — painful cysts. Hormonal acne occurs as a result of an overproduction of sebum because of hormonal fluctuations. Hormonal acne often appears on the chin and jawline, but can be located anywhere.



Skin purging creates breakouts as a result of a reaction to active ingredients in a new skin care product that increase the skin cell turnover rate.


Learn more about skin purging: 



Pustules are a type of pimple. They’re bumps (often red in color) with white pus toward the surface.



Also commonly referred to as “oil,” sebum is the fatty substance secreted by your sebaceous glands. Excess sebum can lead to clogged pores and acne.



Whiteheads form when oil, dead skin cells, or bacteria clog the skin pores or hair follicles. Whiteheads are closed skin pores that are harboring these impurities. They appear as bumps with white pus just below the surface of the skin. 




Acne Rosacea

Acne rosacea is another name for papulopustular rosacea. You may hear this term used less frequently, because it can often become confused with the separate skin condition acne, since both skin conditions involve pimples.


Learn more about acne rosacea:


Products for rosacea-prone skin:


Broken Capillaries

Capillaries are blood vessels responsible for blood circulation in the face. They’re connected to larger veins and arteries. When these blood vessels rupture, they become visible through the skin and are considered “broken capillaries.”



 Erythema is reddening on the surface of the skin caused by dilation of the blood capillaries due to inflammation or injury. It can occur in patches or over a larger area of skin. Erythema can occur on all skin types, but it can be harder for clinicians to identify in darker skin.


Erythematotelangiectatic Rosacea (ETR)

ETR is the type of rosacea most people are familiar with. It causes blushing across the nose and cheeks, but can also appear on the forehead, scalp, chin, and neck if left untreated.


Learn more about erythematotelangiectatic rosacea:



Flushing, also sometimes referred to as facial flushing or flushed skin, refers to a reddening of the skin. It can be caused by a skin condition, such as rosacea, warm weather, exercise, eating spicy food, and even nervousness.


Ocular Rosacea

Ocular rosacea causes inflammation and redness around the eyes and eyelids. It can also cause bumps, swelling, and redness of the eyes, which leads to burning and watering of the eyes.


Learn more about ocular rosacea: 


Papulopustular Rosacea

Also referred to as “acne rosacea,” this type of rosacea not only causes redness and visible blood vessels, but also papules and pustules. These develop deep in the skin, making them difficult to get rid of. These bumps can also be accompanied by abnormally oily or dry patches of skin.


Learn more about papulopustular rosacea:


Phymatous Rosacea

Phymatous rosacea is named after its main symptom: phyma, or a thickening of the skin. It most often occurs on and around the nose and begins as redness and visible blood vessels, progressing to a thickening of the skin. It can result in rhinophyma (see below). 


Learn more about phymatous rosacea: 



Rhinophyma causes an enlarged nose that often appears red, bulbous, and bumpy. It can occur as a result of untreated phymatous rosacea.


Learn more about rhinophyma:


General Skincare



Acidic describes substances that have a pH of below 7. Ideal skin pH is slightly acidic: 4.7–5. When your skin is in the prime 4.7–5 pH range, its acid mantle acts as a barrier to colonization, making it harder for bad bacteria to overgrow.


Learn more about skin pH:



Alkaline describes substances with a pH of over 7. When the skin is too alkaline, it can disrupt skin barrier function and drive inflammation. Alkaline skin appears dull and dry and can lead to wrinkles.


Learn more about skin pH:



Do you see “aqua” listed on your skincare product’s ingredient label? “Aqua” is the International Nomenclature of Cosmetic Ingredients’s name for water. It’s used in many skincare products as a solvent.


Broad Spectrum

When you see a sunscreen labeled “broad spectrum,” that means it protects against both UVA rays and UVB rays. You want to avoid overexposure to both types of rays, which is why this is the type of sunscreen recommended by the American Academy of Dermatology.



Ceramides are lipids, or fats, that make up the epidermis. Ceramides help you retain moisture and maintain a healthy skin barrier. If your ceramide levels decrease, which often happens with age, the skin can become irritated and dry.



Emollients are ointments, lotions, and creams that are designed to soften and smooth the skin and repair the skin barrier. Skincare ingredients including lipids, esters, oils, fatty acids, and butters are also considered emollients.


Fragrance Free

When a skincare product is fragrance-free, it means the product doesn’t contain any fragrances or masking scents. “Unscented” products can still contain masking agents to hide any unpleasant smells. So when you’re avoiding fragrances, fragrance-free products are the best to purchase.



Humectants are ingredients that draw moisture to the surface of the skin. They are key to keeping skin hydrated. Commonly used humectants include glycerin and hyaluronic acid



Hypoallergenic describes a product that contains few allergens. Generally speaking, hypoallergenic skin care products are less likely to induce an allergic reaction.



Inflammation is the body’s natural response to infection or injury. Often, inflammation is the body’s healthy way to defend and heal itself. However, when inflammation becomes chronic, it can wreck havoc on your body. For example, chronic skin inflammation is associated with eczema, rosacea, and acne.



Lipids are the skin’s natural fats that help keep the stratum corneum intact. Ceramides, cholesterol (unrelated to cholesterol in the blood), and fatty acids are all lipids that are key to skin health. Many skincare products contain lipids in order to replenish the skin.



Non-comedogenic is the term used to describe skin care products that are less likely to clog the pores. Non-comedogenic skin care products are recommended for those with acne-prone skin.



Occlusives are ingredients that form a protective layer over the skin in order to help it retain moisture and prevent transepidermal water loss. They can feel greasy or heavy. Commonly used occlusives include petrolatum, mineral oil, waxes, and silicones.



Petrolatum, also known as petroleum jelly, is a mix of mineral oils and waxes that’s used in most ointments. It is an occlusive that forms a protective barrier over the skin and is used to treat dry skin, injured skin and diaper rash. Petrolatum is derived from crude oil.



pH stands for “potential hydrogen.” The term is used in reference to how acidic or alkaline a specific substance is, including your skin. The ideal pH level for the skin is just below 5. When the skin is too alkaline, it can disrupt skin barrier function and lead to bacterial imbalances in the skin microbiome, driving inflammation.


Learn more about skin pH:


Skin Barrier

Your skin barrier, also known as the stratum corneum, is the outermost layer of skin. It’s composed of skin cells known as corneocytes. The corneocytes are held together by a thin lipid layer made up of fatty acids, cholesterol, and ceramides. The composition of the skin barrier is often compared to a brick wall where the cells act as bricks, and the lipid layer functions as mortar. This brick wall functions to protect your body from environmental toxins, airborne threats, chemicals, viruses, and bacteria that could harm you.


Learn more about the skin barrier:



SPF refers to the amount of solar energy, or UV radiation, necessary to result in sunburn on protected skin (like skin with sunscreen on) in comparison to the solar energy needed to create a sunburn on unprotected skin. As SPF increases, sunburn protection increases. For example, SPF 50 protects the skin more than SPF 30.


Stratum Corneum

Your skin barrier is the outermost layer of skin. It’s called the stratum corneum and is composed of skin cells known as corneocytes. The corneocytes are held together by a thin lipid layer made up of fatty acids, cholesterol, and ceramides. The composition of the skin barrier is often compared to a brick wall where the cells act as bricks, and the lipid layer functions as mortar. This brick wall functions to protect your body from environmental toxins, airborne threats, chemicals, viruses, and bacteria that could harm you.


Learn more about the stratum corneum: 


UVA Rays

UVA rays are one of the two types of UV rays emitted by the sun. UVA rays make up approximately 95% of the UV radiation that reaches the earth. UVA rays have a longer wavelength compared to UVB rays — and are associated with skin aging.


UVB Rays

UVB rays are one of the two types of UV rays emitted by the sun. UVB rays have a shorter wavelength than UVA rays — and are associated with skin burning.


Zinc Oxide

Zinc oxide is a common ingredient in mineral sunscreens. It works to protect your skin from UV radiation by reflecting light off the surface of the skin. It occurs naturally as the mineral zincite and is a better option for sensitive skin than other traditional sunscreen ingredients.




Skin Type

In general, the skin can be classified as one of five different skin types: dry, oily, combination, sensitive, and normal. You skin type is influenced by genetics but can change over time and based on environmental and lifestyle factors.


Fitzpatrick Skin Type

The Fitzpatrick Skin Type system was developed in 1975 and classifies your skin based on its amount of pigment. It also factors in your skin’s reaction to sun exposure. Overall, this can help predict your risk of skin cancer or sun damage. Based on the Fitzpatrick Skin Type system, you’ll either be a skin type 1, 2, 3, 4, 5, or 6.



Hyperpigmentation is when excess pigment creates darker patches of skin. This results from extra melanin that makes spots of skin look brown, black, gray, pink, or red. 



The opposite of hyperpigmentation, hypopigmentation occurs when your skin cells don’t produce enough melanin, causing some patches of skin to be lighter than your overall skin tone.



Melanin is a natural pigment responsible for your skin, hair, and eye color. More melanin means darker skin, hair, and eyes. Less melanin results in lighter skin, hair, and eyes.

Dry Skin

One of the five main skin types, dry skin is characterized by rough patches of skin, redness, flaking, dull complexion, less elasticity, and sometimes more visible lines. Dry skin lacks proper sebum (oil) levels and can be eczema-prone.


Oily Skin

Oily skin can be identified by the presence of excess oil on the surface of the skin. The skin may also have enlarged pores and blemishes while appearing shiny. Genetics, stress, puberty and hormonal changes, as well as heat and humidity, can contribute to oily skin.


Combination Skin

Combination skin, one of the five main skin types, is characterized by the presence of both oily and dry areas of skin. Oftentimes, the oily skin appears in the T-zone (the forehead, chin, and nose) while the dry skin shows up on the cheeks and other areas of the face.


Sensitive Skin

If you have a sensitive skin type, your skin is more likely to react to new skin care products, environmental factors, and other stimuli. Sensitive skin is characterized by itching or burning, redness, and dryness.


Dehydrated Skin

If your skin is dehydrated, that means it’s lacking water. Dehydrated skin may appear dull and dry with an uneven complexion. The skin may also be dry and have more noticeable fine lines. It’s important to note that dry and dehydrated skin are often discussed interchangeably, though they’re different. Dry skin lacks sufficient oil, while dehydrated skin lacks water.


Sensitized Skin

Like sensitive skin, sensitized skin may itch or burn and appear red or dry. However, unlike sensitive skin, sensitized skin is not a skin type. Sensitized skin is a skin condition brought on by triggers like medication, overexposure to UV rays, harsh makeup or skin care products, and extreme weather.