Dermatology Dictionary

Common terms used in the General Dermatology Diagnostic Tool

Macules = non-palpable areas of skin change less than 1 cm diameter
Papules = solid elevated lesions less than 0.5 cm diameter
Nodules = solid elevated lesions more than 0.5 cm diameter
Patches 
= flat lesions more than 1 cm diameter
Plaques = circumscribed palpable lesions more than 1cm diameter with a flat top
Pustules
= small pus-filled lesions
Boils
= larger pus-filled lesions
Bullae
 = large fluid-filled blisters
Vesicles = very small fluid-filled blisters
Ulceration
= loss of epidermal skin
Necrosis = black non-viable skin
Structural changes
= firm or weak areas of skin


All dermatology terms (click on the term to view the image) 

Abscess = a pus-containing skin infection / Acute = of rapid onset / Adipose tissue = found underneath the skin and functions as the major fat storage site / Alopecia = hair loss / Anaesthesia = loss of sensation / Annular = ring-shaped / Appendageal = certain structures derived from skin eg, hair, sweat glands and sebaceous glands / Apocrine gland = sweat glands found in areas abundant in hair follicles such as the armpits and groins / Arciform = having the shape of an arch / Asymmetrical = an irregular or uneven shape or pattern eg a skin lesion in which one half looks different to the other, or, a rash that affects one leg much more than the other / Atopy = the genetic tendency to develop the classic allergic conditions of atopic eczema, allergic rhinitis (hay fever), and asthma / Atrophy = thinning or depression of skin due to a reduction in the amount of underlying tissue / Axilla = armpit

Basement membrane = a layer that separates the epidermis (upper skin layer) from the dermis (lower skin layer) / Benign = harmless ie non-cancerous / Bilateral = affecting both sides / Biopsy = a surgical procedure that involves the removal and examination of tissues or cells from the body / Blaschko's lines (the lines of Blaschko) = lines of normal cell development in the skin. These lines are invisible under normal conditions but become apparent when certain skin conditions manifest themselves according to these lines and patterns / Bulla or bullous (blister) = fluid-filled lesion more than 0.5 cm in diameter

Carbuncle or Furuncle = a round, firm and tender boil / Cellulitis = a common deep skin infection caused by bacteria resulting in a localised or spreading area of inflammation / Chronic = persisting for a long time or constantly recurring / Cold sore = a recurrent lesion around the mouth caused by the herpes simplex virus / Collagen = a natural protein found in bone, skin, ligaments, and tendons / Connective tissue = a material made up of fibres forming a framework and support structure for body tissues and organs / Crust = dried exudate or scab / Cryotherapy or cryosurgery = a dermatological procedure done by freezing the lesion with liquid nitrogen / Cyst = a deep-seated lesion filled with fluid or pus

Dermatome = a localised area of skin that has sensation via a single nerve root of the spinal cord / Dermatosis = another name for a skin condition / Dermis = the lower skin layer / Desquamation = skin peeling, ie the shedding of the outermost membrane or layer of the skin / Discoid = coin-shaped / Distal = a point on the skin further away (often in respect of the trunk) eg the wrist is more distal than the elbow, and the knee is more distal than the hip. The opposite of distal is proximal / Distribution = the site of the body affected by a skin lesion or rash / Dorsal = the back of the hand or top of the foot / Drug eruption = a rash caused by injection, ingestion, inhalation, or insertion of a drug / Dystrophy = degeneration or abnormal formation of the skin. It is often used to refer to nail conditions

Ecchymosis = a bruise / Eccrine gland = the main sweat gland, found at most body sites / Epidermis = upper layer of skin / Erythema = a reddening of the skin / Excoriation = a break in the skin caused by scratching / Extremities = distal limbs, hands, feet

Fissure = a cracking or splitting of the skin / Flare = a worsening of a skin condition / Flexural = a body fold, or, the skin on the inner arms and backs of legs / Follicular = involving hair follicles / Fungating = a type of skin lesion that has ulcerations (breaks on the skin), necrosis (death of living tissue) and that usually has a bad smell

Generalised = more widespread skin involvement / Genodermatoses = inherited genetic skin conditions / Granulation tissue = new capillary rich tissue, red in colour, which typically grows from the base of a wound

Hirsutism = excess hair in an androgenic distribution (eg face, chest, upper back) / Horn = a firm projection of keratin / Hyperhidrosis = excess sweating / Hyperpigmentation = darker areas of skin colour / Hypertrichosis = excessive hair growth over and above the normal for the age, sex and race of an individual. It can develop all over the body or can be isolated to small patches / Hypertrophic = an area of skin thickening / Hypopigmentation = white or paler areas of skin colour

Idiopathic = of unknown cause / Immunocompromised or immunosuppressed = a condition where the immune system has been impaired by disease and decreases a person’s ability to fight infection / Indurated = firm / Infant = a child less than 1 year-old / Inflammation = the reaction of the skin that causes redness, swelling, heat, and sometimes pain / Intertrigo = inflammation of body folds

Keloid = a large raised scar, usually but not always resulting from skin injury / Keratinocytes (also called squamous cells) = the main cell found in the epidermis (upper skin layer) / Koebnerisation = the appearance of new skin lesions on areas of skin injury

Lesion = a single area of altered skin, it can be solitary or multiple / Lichenification = an often shiny, flat-topped skin thickening caused by rubbing / Linear = takes the shape of a line / Localised = confined to a small area(s) of skin

Maceration = softened, soggy skin / Macule = a small flat skin discolouration / Malignant = cancerous / Melanin = the pigment that gives human skin, hair, and eyes their colour. Dark-skinned people have more melanin in their skin than light-skinned people have. Melanin is produced by cells called melanocytes / Melanocytes = the cells in the skin that produce the pigment melanin / Morphology = the description of a skin lesion or rash

Natal cleft (sometimes called the sacral cleft) = the area of skin between the buttocks / Necrosis = tissue death, eg of the skin, which turns black / Neonate = an infant less than 4 weeks-old / Neuropathic = a problem caused by nerve dysfunction / Nodule = an elevated skin lesion more than 0.5 cm in diameter

Palmar = palm of hand / Papule = an elevated skin lesion less than 0.5 cm in diameter / Paraesthesia = a prickling or burning sensation in the skin / Paronychia = a painful swelling around a fingernail or toenail / Patch = a larger flat area of skin discolouration / Pedunculated = a skin lesion that sits on a stalk / Perianal = situated in or affecting the area around the anus / Perineal = the area in front of the anus extending to the fourchette of the vulva in the female and to the scrotum in the male / Perioral = around the mouth / Periorbital = around the eye / Photodermatosis = a skin condition triggered by light / Plantar = bottom of foot / Plaque = a raised flat-topped lesion / Polymorphous = many different shapes or patterns / Proximal = a point on the skin closer (often in respect of the trunk) eg the shoulder is more proximal than the elbow, and the elbow is more proximal than the wrist. The opposite of proximal is distal / Pruritus = itch / Purpura = red-purple spots on the skin that do not blanch (become pale) on applying pressure / Pustule = pus-filled lesion

Recalcitrant = resistant to treatment / Reticular = net-like

Scale = visible and palpable flakes of skin / Sebaceous gland = a small gland in the skin which secretes a lubricating oily matter (sebum) in to the hair follicles to lubricate the skin and hair / Seborrhoeic = related to the sebaceous glands (grease producing glands) / Sessile = a soft skin lesion with a relatively broad base / Sweat gland = a small gland in the skin that secretes sweat. Such glands are found over most of the body and have a simple coiled tubular structure / Symmetrical = an even shape or pattern eg a round or oval skin lesion, or a rash that affects both sides of the body in a fairly equal manner / Subcutaneous = underlying the skin

Telangiectasia = a dilatation of small blood vessels, often multiple in character. They appear in the skin as small red lesions, sometimes spidery in appearance, which blanch (become pale) on pressure / Tender = painful when touched / Trunk = all or any part of the chest, abdomen or back

Ulceration = loss of epidermis / Umbilical = involving the naval (tummy button) / Unilateral = affecting one side

Verrucous = warty / Vesicle = fluid-filled lesion less than 0.5 cm in diameter

Wheal and flare = wheal (black arrow) is the raised area caused by cutaneous oedema, flare is the surrounding red area (blue arrow)

Xerosis = excessive dryness of the skin

Zoonosis = a disease which can be transmitted from animals to humans