Acne Glossary
Atrophy: A wasting away; a decrease in size of a tissue or body part.
Azelaic acid: Natural chemical produced by yeast. Used as a topical
agent to treat acne and rosacea. It can also be used to lighten
the skin.
Basal layer: The lowermost layer of the epidermis. This layer provides
replacement cells that travel upward and replenish the skin
with new cells.
Benzoyl peroxide: Topical antibacterial agent used to treat acne.
Found in more over-the-counter and prescription products than
any other topical agent.
Beta hydroxy acids (BHAs): A class of acids, including salicylic
acid, that are used as exfoliants. They’re found in many over-thecounter
acne and cosmetic products, such as moisturizers and
sunscreens. They’re also used in chemical peels.
Blackhead: An open comedo. The dark acne lesion that consists
of a plug of keratin and sebum. The dark color is due to a buildup
of melanin.
Blue light therapy: Visible light treatment that works by killing the
acne-producing bacteria, P. acnes, for a short period of time.
Chemical peel: Application of chemicals to the face in order to
exfoliate the outer layer of skin cells.
Clindamycin: Topical antibiotic often used in the treatment
of acne.
Closed comedo: See whitehead.
Collagen: Resilient protein that provides rigidity and strength to
the dermis. Plays a major role in repairing damage to the skin and
the development of all scars, including acne scars.
Comedo: Plug of keratin and sebum within a hair follicle. It can
appear as a blackhead or a whitehead. The plural form is
comedones.
Comedo extraction: A procedure performed with a round loop
that’s used to apply pressure to dislodge the contents of blackheads
and whiteheads.
Comedogenic: Products that induce the formation of comedones
(blackheads and whiteheads).
Comedogenesis: Medical term for the process that forms whiteheads
and blackheads.
Comedolytic: Signifies that the product breaks up and inhibits
comedo formation.
Comedonal acne: See non-inflammatory acne.
Contact dermatitis: Allergic reaction or irritant response to things
that have touched your skin. Poison ivy and poison oak are classic
examples.
Corticosteroid: Natural hormones produced in the adrenal glands.
When used therapeutically, they are powerful anti-inflammatory
drugs used to treat many types of inflammation.
Cyst: A fluid-filled mass that is usually benign. When someone has
acne, the term cyst is often used interchangeably to mean nodule
because of the resemblance of a nodular acne lesion to a cyst.
Depilatories: Creams, lotions, or powders that contain chemicals
that split the chemical bonds in hair, breaking them off slightly
below the surface of the skin.
Dermabrasion: Method to remove the skin’s top layers and reduce
acne scars using a rapidly rotating wheel or brush attached to a
motorized handle to perform high-speed sanding. Newer technologies,
such as lasers, have largely supplanted this procedure.
Dermatitis: Irritation or inflammation of the skin. A general term
that refers to an itchy red rash. It is sometimes called eczema.
Dermis: Layer of the skin just beneath the epidermis. Contains
blood and lymphatic vessels, hair follicles, nerves, and glands.
Also called the cutis.
Doxycycline: An oral tetracycline antibiotic used to treat acne
and rosacea.
Eczema: See dermatitis.
Elastin fibers: Found in the dermis, these protein structures are
able to coil and recoil like a spring. They give the skin its elasticity.
Electrolysis: A permanent way to remove hair. It destroys hairs
with electrical or thermal energy.
Emollient: Topical applications that are used to correct dryness
and scaling of the skin.
Endocrine system: System of ductless glands that regulates bodily
functions via hormones secreted into the bloodstream. Includes
the hypothalamus, pituitary gland, thyroid, adrenal glands, and
gonads (ovaries and testes).
Endocrinopathy: A disease of endocrine glands. A medical term
for a hormonal disorder.
Enzymes: Proteins that cause a chemical change in other substances
without being changed themselves.
Epidermis: Outer layer of the skin that lies upon the dermis.
Erector pilorum: See hair erector muscle.
Erythromycin: Oral and topical antibiotic that’s often used in the
treatment of acne.
Estrogen: Female hormone produced in the ovaries and adrenal
glands.
Exfoliation: Removal of the outer layers of skin. It can be achieved
with scrubs, glycolic and salicylic acids (chemical peels), as well
as by microdermabrasion.
Fibroblasts: Cells that produce collagen.
Folliculitis: Inflammation of the hair follicles. It can be due to
infections or eczema.
Hair canal: Part of the hair follicle through which sebum travels
onto the hairs before it is carried out to the exterior of your skin.
Hair erector muscle (erector pilorum): Muscle connected to each
hair follicle and the skin. When it contracts, it results in an erect
hair and a goosebump on the skin.
Hair follicle: Tube-shaped covering that surrounds the part of the
hair that is under the skin. Blockage of the follicle is produced by a
follicular plug and is an important step in the formation of acne.
Heredity: Genetic transmission of a particular quality or trait from
parent to offspring.
Hirsutism: Excessive growth of thick dark hair in locations where
hair growth in women usually is minimal or absent. Usually occurs
in androgen-stimulated locations, such as the face, chest, and
around the nipples. May be a sign of polycystic ovary syndrome
in women.
Hormones: The body’s chemical messengers produced by the
endocrine glands. They travel through the bloodstream and have
specific effects on cells and organs in other parts of the body.
Hydroquinone: Chemical that’s used to lighten (bleach) the skin.
Hyperpigmentation: Abnormal darkening of the skin that can
follow inflammation; caused by higher amounts of melanin in a
particular spot. It can also result from hormones and sun exposure.
Hypertrophic scar: Scars that bulge outward like hard lumps. The
word hypertrophy means “enlargement” or “overgrowth.”
Inflammation: A reaction of the skin to disease or injury.
Inflammatory acne: In this type of acne, papules or pustules, red
or purple macules, and nodules, often termed “cysts,” are predominant.
There are few, if any, comedones.
Intense pulsed light treatment (IPL): Devices similar to lasers but
use a wider range of wavelengths as opposed to only a single beam
of light. They employ a broad band of visible and near infrared
wavelengths of light that block out other wavelengths. It is hoped
that they may able to affect the growth and activity of the sebaceous
gland and help to treat acne.
iPLEDGE: An isotretinoin federal registry program geared toward
reducing the number of birth defects, miscarriages, and abortions
associated with isotretinoin. The registry keeps tabs on all
isotretinoin prescriptions in the United States.
Isotretinoin: Chemical (generic) name for Accutane.
Keloid: Large scar whose size goes far beyond what would be
expected from what seems to be a minor injury.
Keratin: Tough, fibrous protein that is inside the cells of the epidermis.
It’s also a constituent of hair and nails.
Keratinization: A process through which keratinocytes produce
the protein keratin.
Keratinocytes: Make up the majority of the cells in the epidermis.
Keratosis pilaris: A condition of small, rough patches that tends to
be mistaken for acne. It usually appears on the arms and sometimes
on the cheeks.
Laser: Lasers produce single (concentrated) bands of light that can
penetrate into the dermis without injuring the epidermis. They’re
used to treat acne and its scars. When used to treat acne, the
beams are adjusted to penetrate below the epidermis and travel
into the dermis where they can zero in on hair follicles, sebaceous
glands, and the P. acnes bacteria.
Lesion: A mark in the skin. In dermatology, refers to a sore, growth,
blister, or any other type of tissue damage caused by injury or
disease.
Lipocytes: Fat cells.
Macule: Flat red, purple, or brown lesion that forms where a
papule or pustule used to be. Remains visible for a while after an
acne lesion has healed or is in the process of healing.
Melanin: Substance that gives the skin and hair its color and protects
us against UV radiation.
Melanocyte: Cell in the epidermis that produces melanin.
Menopause: End of menstruation. The stage in life when women no
longer have periods.
Menstruation: The periodic flow of blood from the uterus. Irregular
menses can indicate a hormonal imbalance that can worsen acne.
Metronidazole: An antibiotic and antiparasitic drug that’s used
topically to treat rosacea.
Microcomedo: First stage of comedo formation; a comedo so small
that it can be seen only with a microscope.
Microdermabrasion: Technique that uses aluminum oxide crystals
passing through a vacuum tube to exfoliate surface skin.
Minocycline: An oral tetracycline antibiotic used to treat acne
and rosacea.
Nodule: A large and lumpy, pus-filled, frequently reddish bump
that is lodged more deeply in the skin. They are inflammatory
lesions that are sometimes referred to as cysts.
Noncomedogenic: Skin-care products that have been tested and
proven not to clog pores and produce comedones.
Noncomedonal acne: See inflammatory acne.
Non-inflammatory acne: This category of acne is identified when
a person’s lesions are primarily whiteheads and blackheads. It is
also called comedonal acne.
Ocular rosacea: Rosacea that involves the eyes.
Open comedo: See blackhead.
Oral contraceptives: Drugs used to help prevent an unwanted
pregnancy. If you’re female, your doctor may also prescribe them
to fight acne by virtue of their anti-androgenic effects.
Oral therapy: Something that’s taken by mouth such as a pill, capsule,
or liquid.
Papule: Pimples (zits) that appear as small, firm, reddish bumps
on the skin. They are inflammatory lesions.
Perimenopause: The transitional period from normal menstrual
periods to no periods at all.
Perioral dermatitis: Also known as periorificial dermatitis, this condition
is a rosacea-like skin eruption seen almost exclusively in
young women.
Pilosebaceous unit: Grouping of the hair follicle and its attached
sebaceous gland.
Polycystic ovary syndrome: PCOS is characterized by menstrual
irregularities, hirsutism, acne, ovarian cysts, varying degrees of
insulin resistance, and often, obesity.
Pomade acne: Type of acne is seen in African-Americans and other
individuals who have tight curly hair and frequently use pomade
(oils and greasy ointments) to style or improve their hair’s
manageability.
Pores: The openings of hair follicles onto the skin. Through them,
sweat and sebum flow onto the skin.
Postinflammatory hyperpigmentation: These dark spots are also
called postinflammatory pigmentation, or PIP, for short. The original
insult (and injury) that caused PIP can be a cut, a burn, a rash,or the after-effect from a healing acne lesion. The dark spots are
limited to the sites of previous inflammation.
Prednisone: Synthetic corticosteroid that’s used to treat inflammatory
conditions.
Progesterone: Female hormone produced by the ovaries after
ovulation to prepare the uterus for fertilization.
Progestin: Synthetic progesterone.
Propionibacterium acnes (P. acnes): These bacteria are an integral
part of producing the inflammatory lesions of acne. They
live in the pilosebaceous glands of the skin.
Pseudofolliculitis barbae (razor bumps): Acnelike lesions that
occur mainly on the beard area in men of African heritage. This
condition is due to curly, ingrown hairs.
Pulse dye laser (PDL): This laser is “tuned” to a specific wavelength
of light. It produces a bright light that is absorbed by the superficial
blood vessels of the skin. The abnormal blood vessels are destroyed
without damaging the surrounding skin. This laser has been used
to successfully treat acne scars and rosacea telangiectasias.
Punch excision: Surgical technique that’s sometimes used to cut
out and reduce certain types of acne scars.
Pustule: A papule that contains pus. It’s also known as a pus
pimple. An inflammatory lesion.
Resorcinol: A weakly acidic organic chemical obtained from various
resins; found in some topical agents used to treat acne.
Retinoids: Chemicals related to vitamin A. A mainstay in the treatment
of both comedonal and inflammatory acne. The major
retinoids are Retin-A, tretinoin, Tazorac, and Differin.
Retention hyperkeratosis: Excessive buildup of skin cells that,
combined with sebum and trapped bacteria, creates a plug in hair
follicles that results in acne lesions.
Rhinophyma: Enlarged nose that results from enlarged sebaceous
glands and overgrowth of collagen, and is a feature of rosacea
that’s seen primarily in men.
Rosacea: Acnelike condition characterized by redness, papules,
and sometimes pustules in the center one third of the face in certain
fair-complexioned adults. It’s often mistaken for acne.
Salicylic acid: Ingredient found in many over-the-counter acne
products. Helps to exfoliate the outer layers of the skin.
Sebaceous duct: Tiny tube that steers the sebum (and the dead
skin cells it carries) from the sebaceous gland into the hair
canal.
Sebaceous glands: Located in the dermis next to hair follicles,
these are small, sack-shaped glands that release sebum onto the
hair and moisturize the skin.
Sebum: Oily substance produced by sebaceous glands that coats
the hair and skin. Composed of a rich blend of different lipids (fatty
chemicals). Helps to keep the skin lubricated and protected. Clogs
pores, helping to cause outbreaks of acne.
Sex hormone binding globulin: A protein in the blood that “mops
up” free testosterone and prevents it from stimulating acneproducing
oil glands to produce excess oil.
Spironolactone: An anti-androgen medication sometimes used in
combination with oral contraceptives to treat acne in women.
Stratum corneum: Also known as the horny layer, it is the outermost
layer of the epidermis. It is comprised of dead skin cells that
protect deeper cells from damage, infection, and from drying out.
Stratum spinosum: This is the middle (“spiny”) layer of the epidermis.
These cells are always actively dividing.
Subcutaneous layer: Fatty layer of tissue located under the
dermis.
Sulfacetamide: Anti-infective used topically to treat acne and
rosacea. Often combined with sulfur.
Telangiectasias: Small, dilated blood vessels usually seen on the
face. Also called broken blood vessels, or “spider veins.”
Teratogenic: Drug that, if taken during pregnancy, is highly likely
to cause severe birth defects.
Testosterone: An androgen and the main male hormone.
Produced by the testes in men and by the ovaries in women.
Tetracycline: Oral antibiotic typically used to treat acne and
rosacea.
Topical therapy: Something that’s applied onto the skin, such as a
cream, gel, or ointment.
Vehicle: Part of a product that holds the active ingredient. It’s the
base (ointment, gel, or cream) to which a medication is added.
Whitehead: Small, pearly white acne lesion that consists of a plug
of keratin and sebum. Occurs when the comedo stays below the
surface of the skin. Also called a closed comedo.
