Glossary
The language of skin.
85 terms your dermatologist might use, each explained in a sentence or two. Every term has its own link you can share.
A
- Acanthosis nigricans
- Dark, thickened, velvety skin in body folds such as the neck and underarms. It is often linked to insulin resistance, obesity or hormonal conditions like PCOS. Read: Dark Underarms and Neck: Acanthosis Nigricans Explained
- Acne vulgaris
- A common skin condition in which hair follicles become blocked with oil and dead skin, leading to blackheads, whiteheads, pimples and sometimes cysts. Read: Acne on Indian Skin: Causes, Treatment and What Actually Works
- Actinic keratosis
- A rough, scaly patch on sun-damaged skin. A small number can turn into skin cancer, so they are worth having checked.
- Allergen
- A substance that triggers an allergic reaction in a sensitive person, such as nickel, fragrance or certain preservatives.
- Alopecia
- The medical word for hair loss. It covers many types with different causes, from genetic thinning to autoimmune patchy loss. Read: Hair Fall in Women: Causes, Tests and Treatment in India
- Alopecia areata
- An autoimmune condition in which the immune system attacks hair follicles, causing round, smooth patches of hair loss. Read: Alopecia Areata: Causes and Treatment of Patchy Hair Loss
- Androgenetic alopecia
- Hereditary hair thinning influenced by hormones. In men it is called male pattern baldness and in women female pattern hair loss. Read: Male Pattern Baldness Treatment: What Actually Works
- Angioedema
- Swelling in the deeper layers of the skin, often around the eyes, lips or throat. Swelling of the throat or tongue is an emergency. Read: Urticaria (Hives): Causes, Relief and When to Worry
- Antioxidant
- A molecule that helps neutralise free radicals, unstable molecules produced by UV light and pollution that can damage skin cells. Vitamin C is a common example in skincare. Read: Vitamin C and Niacinamide Serums Explained for Indian Skin
- Atopic dermatitis
- The most common type of eczema. It causes dry, itchy, inflamed skin and often starts in childhood, sometimes alongside asthma or hay fever. Read: Eczema (Atopic Dermatitis) in Adults and Children
B
- Barrier function
- The ability of the outermost skin layer to keep water in and irritants out. A damaged barrier shows up as dryness, stinging and sensitivity. Read: Basic Skincare Routine by Skin Type: A Dermatologist's Guide
- Biopsy
- Removal of a small piece of skin so it can be examined under a microscope to confirm a diagnosis.
- Broad spectrum
- A sunscreen label meaning the product protects against both UVB rays, which cause burning, and UVA rays, which cause tanning, ageing and pigmentation. Read: Sunscreen Guide for India: SPF, PA Ratings and How to Apply
C
- Ceramides
- Fats naturally found in the outer skin layer that help hold skin cells together and support the barrier. Many moisturisers contain them.
- Chemical peel
- A procedure in which a dermatologist applies an acid solution to remove the outer layers of skin, used for pigmentation, acne and texture. Read: Chemical Peels for Indian Skin: Types, Benefits and Safety
- Collagen
- The main structural protein in the dermis that gives skin its firmness. Its production falls with age and sun exposure.
- Comedogenic
- Describes a product or ingredient that tends to block pores and may worsen acne. Non-comedogenic products are formulated to avoid this.
- Comedone
- A clogged hair follicle. An open comedone is a blackhead and a closed comedone is a whitehead. Read: Acne on Indian Skin: Causes, Treatment and What Actually Works
- Contact dermatitis
- An itchy rash caused by something touching the skin, either an irritant such as detergent or an allergen such as nickel.
- Cyst
- A closed sac under the skin that can contain fluid or other material. In acne, deep painful cysts can leave scars.
D
- Dermatitis
- A general term for inflammation of the skin, usually with redness, itching and sometimes scaling or blisters.
- Dermatologist
- A doctor who has completed specialist training in diagnosing and treating conditions of the skin, hair and nails. In India this usually means an MD or DNB in dermatology.
- Dermatophyte
- A group of fungi that feed on keratin in the skin, hair and nails. They cause tinea (ringworm) infections, including jock itch, athlete's foot and many nail infections. Read: Ringworm (Tinea) in India: Why It Keeps Coming Back
- Dermis
- The thick middle layer of skin beneath the epidermis. It contains collagen, blood vessels, nerves, hair follicles and sweat glands.
- Dermoscopy
- Examination of the skin with a handheld magnifying device and light, which helps a dermatologist assess moles, hair loss and other conditions.
E
- Eczema
- A group of conditions that cause dry, itchy and inflamed skin. Atopic dermatitis is the most common form. Read: Eczema (Atopic Dermatitis) in Adults and Children
- Epidermis
- The thin outermost layer of skin. It forms the protective barrier and contains melanocytes, the cells that make pigment.
- Erythema
- Redness of the skin caused by increased blood flow, seen in inflammation, sunburn and many rashes.
- Exfoliation
- Removal of dead cells from the skin surface, either with acids and enzymes (chemical) or with scrubs and tools (physical).
F
- Fitzpatrick skin type
- A six-point scale that groups skin by how it reacts to sun, from type I (always burns) to type VI (deeply pigmented, rarely burns). Most Indian skin falls between types III and VI.
- Folliculitis
- Inflammation of hair follicles, often appearing as small red or pus-filled bumps. It can be caused by bacteria, yeast or friction. Read: Fungal Acne (Malassezia Folliculitis): Signs and Treatment
H
- Hair follicle
- The small pocket in the skin from which a hair grows. Oil glands open into it.
- Hives
- Raised, itchy welts on the skin that come and go, also called urticaria. Read: Urticaria (Hives): Causes, Relief and When to Worry
- Humectant
- An ingredient that draws water into the outer skin layer, such as glycerin or hyaluronic acid.
- Hyaluronic acid
- A molecule that holds water and is found naturally in skin. In skincare it is used as a humectant to improve hydration.
- Hyperhidrosis
- Sweating that is much more than the body needs to control temperature, most often on the palms, soles, underarms or face. It can be primary, with no underlying cause, or secondary to another condition or medicine. Read: Hyperhidrosis: When Sweating Is More Than the Indian Heat
- Hyperpigmentation
- Areas of skin that are darker than the surrounding skin because of extra melanin. Melasma and dark spots after acne are common examples. Read: Dark Spots After Pimples (PIH): How to Fade Them on Indian Skin
- Hypopigmentation
- Areas of skin that are lighter than the surrounding skin because of reduced melanin.
I
- Iontophoresis
- A treatment for excessive sweating of the hands or feet in which they are placed in shallow water while a mild electrical current is passed through it. It is usually repeated over several sessions and then continued as maintenance. Read: Hyperhidrosis: When Sweating Is More Than the Indian Heat
- Isotretinoin
- An oral retinoid medicine prescribed for severe, scarring or treatment-resistant acne. It needs a prescription and medical monitoring, and it must not be taken during pregnancy because it causes serious birth defects. Read: Isotretinoin for Acne: What Patients Should Know
K
- Keloid
- A raised, firm scar that grows beyond the edges of the original wound. Keloids are more common in darker skin types.
- Keratin
- A tough protein that makes up hair, nails and the outer layer of skin.
- Keratosis pilaris
- A common, harmless condition in which keratin plugs hair follicles, causing small rough bumps, often on the upper arms and thighs. It is sometimes called chicken skin and tends to improve with age. Read: Keratosis Pilaris (Chicken Skin): Causes and Gentle Care
L
- Laser hair reduction
- A procedure that uses laser light absorbed by pigment in the hair to damage follicles and reduce regrowth over a series of sessions. Read: Laser Hair Reduction on Indian Skin: Safety, Sessions, Risks
- Lichen planus
- An inflammatory condition that causes itchy, flat-topped, purplish bumps on the skin and can also affect the mouth, nails and scalp.
M
- Malassezia
- A yeast that normally lives on the skin. It can overgrow and play a role in dandruff, seborrheic dermatitis, pityriasis versicolor and fungal acne. Read: Fungal Acne (Malassezia Folliculitis): Signs and Treatment
- Melanin
- The pigment that gives skin, hair and eyes their colour and helps protect skin from UV damage.
- Melanocyte
- A cell in the base of the epidermis that makes melanin.
- Melasma
- A common condition causing brown or grey-brown patches, usually on the cheeks, forehead and upper lip. Sun exposure and hormones are major triggers. Read: Melasma Treatment for Indian Skin: What Works and What to Avoid
- Microneedling
- A procedure that uses fine needles to create tiny controlled injuries in the skin, prompting it to produce new collagen. Used for acne scars and texture. Read: Microneedling and PRP: What to Expect, Risks and Downtime
- Milia
- Tiny, hard, white bumps caused by keratin trapped under the skin surface, common around the eyes.
- Miliaria
- A rash of tiny bumps caused by blocked sweat ducts, also known as prickly heat or sweat rash. It is common in hot, humid weather. Read: Prickly Heat, Sweat Rash and Monsoon Skin Care in India
- Minoxidil
- A medicine that can slow hair loss and help regrowth in pattern hair loss, used as a solution or foam on the scalp and sometimes prescribed as tablets. It works only while it is used, and some shedding in the first weeks is common. Read: Minoxidil for Hair Loss: What to Know Before You Start
- Mole
- A common growth made of clusters of melanocytes, also called a naevus. A mole that changes in size, shape or colour should be checked.
- Molluscum contagiosum
- A common viral skin infection that causes small, firm, pearly bumps with a central dimple, seen most often in children. It spreads by skin contact and usually clears by itself over months. Read: Warts, Molluscum and Corns: How to Tell Them Apart
N
- Niacinamide
- A form of vitamin B3 used in skincare to support the skin barrier, reduce redness and help with uneven tone. Read: Vitamin C and Niacinamide Serums Explained for Indian Skin
O
- Onycholysis
- Separation of the nail plate from the nail bed, which makes the detached part look white or yellow. Causes include injury, fungal infection, psoriasis, thyroid disease and some medicines. Read: Nail Fungus (Onychomycosis): Why It Is Slow to Treat
P
- PA rating
- A rating used on Asian sunscreens to show the level of UVA protection, from PA+ to PA++++. More plus signs mean more UVA protection. Read: Sunscreen Guide for India: SPF, PA Ratings and How to Apply
- Papule
- A small, raised, solid bump on the skin, less than about 1 cm across.
- Patch test
- A test in which small amounts of possible allergens are applied to the skin to find the cause of contact allergy. Also used informally for trying a new product on a small area first.
- Photosensitivity
- Increased sensitivity of the skin to sunlight, which can be caused by some medicines, skincare ingredients or medical conditions.
- Phototherapy
- Treatment with controlled doses of ultraviolet light, such as narrowband UVB, used for conditions like vitiligo, psoriasis and eczema. Read: Vitiligo: Causes, Treatment and Common Myths in India
- Pityriasis versicolor
- A common yeast infection that causes light or dark scaly patches, usually on the chest, back and shoulders. It is frequent in hot, humid weather.
- Post-inflammatory hyperpigmentation
- Dark marks left behind after skin inflammation or injury, such as acne, eczema or a burn. It is more common and lasts longer in darker skin. Read: Dark Spots After Pimples (PIH): How to Fade Them on Indian Skin
- PRP
- Platelet-rich plasma. A concentrate made from your own blood that is injected or applied to the scalp or skin, used for some types of hair loss and scarring. Read: Microneedling and PRP: What to Expect, Risks and Downtime
- Pruritus
- The medical word for itching.
- Psoriasis
- A long-term immune condition that causes thick, red or darker, scaly plaques, often on the elbows, knees, scalp and lower back. Read: Psoriasis: Symptoms, Triggers and Treatment Options
- Pustule
- A small bump on the skin that contains pus.
R
- Retinoid
- A family of vitamin A derived ingredients and medicines, including retinol and tretinoin, used for acne, pigmentation and signs of ageing. Read: Retinol vs Tretinoin: A Beginner's Guide to Retinoids
- Rosacea
- A long-term condition causing facial redness, flushing, visible blood vessels and sometimes acne-like bumps. Read: Rosacea and Sensitive Skin: Symptoms, Triggers and Care
S
- Scabies
- An intensely itchy skin infestation caused by a tiny mite. It spreads through close contact and the whole household usually needs treatment.
- Sebaceous gland
- A small gland in the skin, attached to a hair follicle, that produces oil called sebum.
- Seborrheic dermatitis
- A common condition that causes red, flaky, sometimes itchy patches on oily areas such as the scalp, eyebrows and sides of the nose. Dandruff is its mildest form. Read: Dandruff and Seborrheic Dermatitis: Causes and Treatment
- Sebum
- The oily substance produced by sebaceous glands that helps keep skin and hair moisturised. Excess sebum contributes to acne.
- SPF
- Sun protection factor. A measure of how well a sunscreen protects against UVB rays, which cause sunburn. Read: Sunscreen Guide for India: SPF, PA Ratings and How to Apply
T
- Telogen effluvium
- Temporary, diffuse hair shedding that often starts two to three months after a trigger such as illness, fever, childbirth or major stress. Read: Hair Fall in Women: Causes, Tests and Treatment in India
- Tinea
- A fungal infection of the skin, hair or nails, commonly called ringworm. Tinea corporis affects the body and tinea cruris the groin. Read: Ringworm (Tinea) in India: Why It Keeps Coming Back
- Topical corticosteroid
- An anti-inflammatory medicine applied to the skin. Effective when prescribed, but misuse, especially in mixed fairness creams, can cause serious side effects. Read: Steroid Creams and Fairness Creams: The Hidden Danger
- Transepidermal water loss
- Water that evaporates from the body through the skin. It increases when the skin barrier is damaged.
U
- Urticaria
- Raised, itchy welts on the skin, also called hives. Chronic urticaria lasts longer than six weeks. Read: Urticaria (Hives): Causes, Relief and When to Worry
- UVA
- Long-wave ultraviolet light that penetrates deep into the skin and contributes to tanning, pigmentation and ageing. It passes through clouds and glass. Read: Sunscreen Guide for India: SPF, PA Ratings and How to Apply
- UVB
- Short-wave ultraviolet light that mainly affects the surface of the skin and is the main cause of sunburn. Read: Sunscreen Guide for India: SPF, PA Ratings and How to Apply
V
- Vitiligo
- A condition in which the skin loses its pigment cells, causing white patches. It is not contagious. Read: Vitiligo: Causes, Treatment and Common Myths in India
W
- Wart (verruca)
- A small, rough growth on the skin caused by the human papillomavirus (HPV), common on the hands and feet. Warts are contagious, and many go away on their own, though this can take months to years. Read: Warts, Molluscum and Corns: How to Tell Them Apart
- Wood's lamp
- A handheld ultraviolet lamp used in the clinic to examine the skin. It helps assess pigment changes, vitiligo and some infections.