Chapter 9: The Skin - Structure, Disorders, and Diseases

A comprehensive collection of vocabulary terms and definitions regarding skin structure, disorders, and diseases based on the Chapter 9 glossary.

Acne

Skin disorder characterized by chronic inflammation of the sebaceous glands from retained secretions

Adipose tissue

A technical term for fat; gives smoothness and contour to the body

Albinism

Congenital leukoderma, or absence of melanin pigment in the body

Anhidrosis

A deficiency in perspiration or the inability to sweat, often a result of damage to autonomic nerves

Asteatosis

A condition of dry, scaly skin, characterized by the absolute or partial deficiency of sebum

Basal cell carcinoma

Most common and least severe type of skin cancer

Blackhead

An open comedone; consists of an accumulation of excess oil (sebum) that has been oxidized to a dark color

Bromhidrosis

Foul-smelling perspiration

Bulla

Large blister containing a watery fluid

Chloasma

Non-elevated spots due to increased pigmentation in the skin

Closed comedo

Also known as a whitehead; a small bump just under the skin surface with white or cream colored sebum

Collagen

Fibrous protein that gives the skin form and strength

Comedone

A mass of hardened sebum and skin cells in a hair follicle that may be open (blackhead) or closed (whitehead)

Crust

Dead cells that have accumulated over a wound while healing

Cyst

A closed, abnormally developed sac containing fluid or morbid matter, above or below the skin

Derma

Technical name for skin; also another name for the dermis

Dermatitis

An inflammatory condition of the skin

Dermatitis venenata

Also known as irritant contact dermatitis; an eruptive skin condition due to contact with irritating substances such as tints or chemicals

Dermatology

A branch of medical science that deals with the study of the skin

Dermis

Second or inner layer of the skin; also known as the derma, corium, cutis, or true skin

Dyschromias

Abnormal skin colorations

Eczema

Inflammatory skin condition characterized by painful itching; dry or moist lesion forms

Elastin

Protein base similar to collagen that forms elastic tissue

Epidermis

Outermost layer of the skin; also called the cuticle or scarf skin

Excoriation

Skin sore or abrasion caused by scratching or scraping

Fissure

A crack in the skin that penetrates to the dermis

Herpes simplex 1

Fever blister or cold sore; a recurring viral infection

Hyperhidrosis

Excessive perspiration or sweating

Hyperpigmentation

Darker than normal pigmentation, appearing as dark splotches

Hypertrophy

Abnormal skin growth

Hypopigmentation

The absence of pigment, resulting in light or white splotches

Irritant contact dermatitis

Abbreviated ICD; also known as dermatitis venenata; occurs when irritating substances temporarily damage the epidermis

Ivy dermatitis

A skin inflammation caused by exposure to poison ivy, poison oak, or poison sumac

Keloid

Thick scar resulting from excessive tissue growth

Keratoma

Technical name for a callus, caused by pressure or friction

Lentigines

Technical name for freckles

Lesion

A structural change in the tissues caused by injury or disease

Leukoderma

Skin disorder characterized by abnormal white patches

Macule

Spot or discoloration of the skin, such as a freckle

Malignant melanoma

Most severe form of skin cancer

Melanin

Coloring matter or pigment of the skin; found in the stratum germinativum of the epidermis and in the papillary layers of the dermis

Milia

Technical name for milk spots; small, benign, whitish bumps that occur when dead skin is trapped in the surface of the skin; commonly seen in infants

Miliaria rubra

Also known as prickly heat, is an acute inflammatory disorder of the sweat glands, characterized by the eruption of small red vesicles accompanied by burning, itching skin

Mole

Small brownish spot on the skin

Motor nerve fibers

Nerve fibers distributed to the arrector pili muscles, which are attached to the hair follicles

Nevus

Technical name for a birthmark

Nodule

A solid bump larger than $0.4 \, \text{inches} \, (1 \, \text{cm})$ that can be easily felt

Open comedo

Also known as a blackhead; a hair follicle filled with keratin and sebum

Papillary layer

Outer layer of the dermis, directly beneath the epidermis

Papule

A small elevation on the skin that contains no fluid, but may develop pus

Primary skin lesions

Lesions that are a different color than the color of the skin or lesions that are raised above the surface of the skin

Psoriasis

Skin disease characterized by red patches and silvery-white scales

Pustule

Raised, inflamed, papule with a white or yellow center containing pus in the top of the lesion

Reticular layer

Deeper layer of the dermis

Rosacea

Chronic congestion of the skin characterized by redness, blood vessel dilation, papules, and pustules

Scale

An accumulation of dry or greasy flakes on the skin

Scar

Also called cicatrix; a slightly raised or depressed mark on the skin formed after an injury or a lesion of the skin has healed

Sebaceous cyst

A large, protruding pocket-like lesion filled with sebum, frequently seen on the scalp and back

Sebaceous glands

Oil glands of the skin connected to hair follicles

Seborrheic dermatitis

A skin condition caused by an inflammation of the sebaceous glands, and is often characterized by redness, dry or oily scaling, crusting, and/or itchiness

Sebum

An oily substance secreted by the sebaceous glands

Secondary skin lesions

Lesions characterized by an accumulation of material on the skin surface, such as a crust or scab, or by depressions in the skin surface

Secretory nerve fibers

Nerves that regulate the excretion of perspiration from the sweat glands and the flow of sebum from the oil glands

Sensory nerve fibers

Nerves that react to heat, cold, touch, pressure, and pain and send messages to the brain

Skin tag

A small brown-colored or flesh-colored outgrowth of the skin occurring most frequently on the neck and chest

Squamous cell carcinoma

Type of skin cancer more serious than basal cell carcinoma, but not as serious as malignant melanoma

Stain

Abnormal brown- or wine-colored skin discoloration

Steatoma

Sebaceous cyst or fatty tumor

Stratum corneum

Outermost layer of the epidermis; the horny layer

Stratum germinativum

Innermost layer of the epidermis, also known as the basal or Malpighian layer

Stratum granulosum

Granular layer of the epidermis beneath the stratum lucidum; the grainy layer

Stratum lucidum

Clear layer of the epidermis, directly beneath the stratum corneum

Stratum spinosum

Spiny layer of the epidermis, often considered part of the stratum germinativum

Subcutaneous tissue

Fatty tissue layer that lies beneath the dermis; also called adipose tissue

Sudoriferous glands

Sweat glands of the skin

Tan

Darkening of the skin due to exposure to ultraviolet rays

Telangiectasis

Distended or dilated surface blood vessels

Tubercle

Abnormal solid lump above, within, or below the skin

Tumor

Abnormal cell mass resulting from excessive multiplication of cells

Ulcer

Open skin lesion accompanied by pus and loss of skin depth; a deep erosion; a depression in the skin, normally due to infection or cancer

Verruca

Technical name for a wart

Vesicle

Small blister or sac containing clear fluid

Vitiligo

An acquired leukoderma characterized by milky-white spots

Wart

Also known as verruca; an infectious hypertrophy of the papillae and epidermis caused by a virus

Wheal

Itchy, swollen lesion caused by insect bites or plant irritations, such as nettle

Whitehead

A closed comedone; consists of accumulated sebum that remains a whitish color because it does not have a follicular opening for exposure to oxygen