Dermatology Glossary
As doenças de pele mais comuns, explicadas de forma simples. Clique num termo para saber o que é e quando procurar uma consulta.
Velvety darkening of the skin in the folds (neck, armpits), often associated with excess weight or insulin resistance.…
An inflammatory disease of the sebaceous glands and hair follicles, very common in adolescence but also frequent in adults. It shows up as blackheads,…
A small fibrous, scaly projection on a finger or toe; it is benign.…
The common mole, which appears during childhood and youth. Most are and remain benign.…
A pre-malignant lesion on areas of chronic sun exposure: a rough, scaly patch that is felt more than it is seen.…
It appears as weals (raised lesions like a nettle sting) that move from place to place within hours, with itching. The acute form lasts days and is of…
A family of flaps in which neighbouring skin advances in a straight line to cover the surgical defect — each design («A-T», «H», «puzzle»…) addresses …
A skin reaction to a specific substance to which the person has become sensitised — nickel in costume jewellery, fragrances, preservatives, hair dyes,…
Hair loss in well-defined round patches, with an autoimmune cause — the immune system attacks the hair follicles. It can affect the scalp, the beard o…
This is the most common form of hair loss: a progressive thinning of the hair, hereditary and hormonal in origin, which affects men and women in diffe…
A small, dark, keratotic vascular lesion, sometimes mistaken for a melanoma.…
The so-called «cherry angiomas»: small red papules that become more numerous with age.…
Benign vascular lesions — small red dots or patches formed by blood vessels.…
«Genital warts», caused by HPV — the most common sexually transmitted infection. They appear as raised, cauliflower-like lesions in the genital or ana…
A congenital absence of a small area of skin, most often on the scalp, present from birth.…
A chronic inflammatory skin disease, very common in children but also present in adults. The skin becomes dry, with intense itching and flare-ups of e…
A mole with dermoscopic features outside the usual pattern — junctional or compound, with atypia — which requires careful distinction from melanoma.…
An aromatic resin used as a marker of allergy to fragrances and aromas — present in cosmetics and even in foods.…
The most common skin cancer — and the one with the best prognosis. It grows slowly, almost never spreads to other organs, and appears on chronically s…
An extensive brown patch, sometimes hairy, which typically appears on the shoulder or trunk during adolescence.…
A blue-grey mole, due to the depth of the pigment within the dermis — usually stable since youth.…
Microinjections of botulinum toxin into the affected area (armpits, palms) that temporarily block the stimulation of the sweat glands.…
Pigmented genital papules associated with HPV, showing histological atypia.…
Another marker of corticosteroid allergy, from a different class.…
The most common autoimmune blistering disease in older people: tense blisters on an urticarial base, with itching.…
A uniform light brown patch, present from an early age. One or two are common and of no significance.…
Local anaesthetics of the benzocaine family, present in "soothing" and haemorrhoid ointments.…
Inflammation of the glans caused by the fungus Candida, with redness, burning and sometimes whitish spots — more common in uncircumcised men and in pe…
The controlled application of substances that renew the surface layers of the skin — helpful for acne, pigmentation patches, photoageing and uneven te…
Long-standing eczema with skin that has become thickened and lichenified from repeated scratching.…
An ablative laser that vaporises tissue with precision — it removes benign lesions (keratoses, syringomas, xanthelasmas) and, in fractional mode, rene…
A metal found in alloys, cement and paints — frequently associated with nickel allergy.…
Pine resin found in adhesives, plasters, waxes and resins — a common cause of eczema from plasters.…
A line or cluster of grouped "blackheads", present from early in life — a naevus of the hair follicles.…
The common wart of the hands and fingers, caused by HPV, very frequent in school-age children.…
A genital wart caused by HPV — see «Anogenital condylomata acuminata».…
A deviation in the growth of the big toenail, present from birth, which may lead to ingrowing.…
A mole present at birth, of varying size. Small ones carry a very low risk; giant ones require dedicated monitoring.…
Small, slightly raised skin-coloured plaques caused by a localised excess of collagen or elastin.…
Treatment with cold: liquid nitrogen is applied to destroy benign or pre-malignant lesions in a controlled way — warts, actinic and seborrhoeic kerato…
Removal of superficial lesions with a fine-edged instrument (a curette), under local anaesthetic — useful for seborrhoeic keratoses, molluscum and oth…
An autoimmune disease that may affect the skin alone or form part of a systemic condition. The lesions are typically made worse by the sun, with redne…
A group of lymphomas that appear first in the skin — mycosis fungoides, the most common, progresses slowly with persistent scaly plaques.…
A build-up of mast cells in the skin, with multiple brownish patches that become itchy and raised when rubbed (Darier's sign).…
A benign tumour of the skin appendages, typically on the scalp; multiple cylindromas are hereditary.…
An autoimmune blistering disease with fierce itching on the elbows, knees and buttocks — the skin expression of coeliac disease.…
A preservative (methyldibromo glutaronitrile) already restricted in the EU but still present in older and imported products.…
A translucent cyst next to the nail, connected to the joint, which may cause a groove in the nail.…
A chronic cutaneous form of lupus with well-defined, scaly and atrophic plaques that are made worse by the sun — on the scalp it causes scarring alope…
A textile dye used in dark synthetic fabrics — causes eczema in areas where clothing rubs against the skin.…
Another sensitising textile dye, also used in older hair dyes.…
A chronic inflammatory condition of the scalp with deep nodules, draining tracts and scarring alopecia, most common in young men.…
A reconstruction in which two flaps rotate in opposite directions, forming a final 'Z' shape — useful on the scalp and in round defects where the skin…
A skin reaction to a medicine — ranging from a simple rash to severe forms involving the mucous membranes.…
A form of eczema that appears as small blisters ('little bubbles') with intense itching on the palms of the hands, fingers and soles of the feet, ofte…
The use of high-frequency electrical current to cut or coagulate tissue with great precision — often combined with curettage to remove lesions and con…
A linear, rough birthmark that follows the lines of the skin.…
The common "sebaceous cyst": a lump with a central pore that may become inflamed.…
Two-component adhesives and coatings — used in construction, boating and electronics.…
When the defect left by the removal cannot be closed directly, neighbouring skin — a flap — is moved across to cover it, keeping a similar colour and …
Reconstruction in which the defect is covered with a full-thickness piece of skin taken from another area (behind the ear, the collarbone), chosen to …
Surgical removal of tumours of the nail unit — the nail bed, matrix or nail folds — under local anaesthetic to the finger or toe.…
A variation of excision in which an «M»-shaped design shortens the scar and spares skin in areas where it is precious — such as near the eyes, nose or…
A technique in which the skin is advanced and sutured from a «V» into a «Y» shape, making it possible to close defects where mobility is limited — oft…
Complete surgical removal of a lesion, with adequate margins, closing the skin with direct suturing — the cornerstone technique of dermatological surg…
A variant of lipoma with a fibrous component — a soft, mobile lump under the skin.…
A reaction to a medicine that reappears always at the same site: a round, dark patch that flares up each time the drug is taken.…
Chronic inflammation of the hair follicles of the scalp with recurrent pustules and «tufted hairs», progressing to scarring alopecia.…
Inflammation or infection of the scalp follicles, with spots and pustules that may be painful or itchy.…
A preservative and formaldehyde releaser found in cosmetics, varnishes and starched textiles.…
Groups of the fragrances that most commonly cause sensitisation — found in cosmetics, detergents and air fresheners.…
A form of scarring alopecia in which the hairline gradually recedes at the forehead and temples, often with loss of the eyebrows — most common in wome…
Fungal infections of the skin (tinea) or of the nails (onychomycosis). In the nails they cause thickening, lifting of the nail and colour change; on t…
Conditions such as Osler-Weber-Rendu, Bart syndrome, Buschke-Ollendorff or LEOPARD syndrome show themselves on the skin from an early age.…
Infection with the herpes simplex virus, with recurrent episodes of painful clustered blisters in the genital area.…
Ring-shaped lesions, skin-coloured or pinkish, commonly on the backs of the hands and feet in children and young people. It is benign and not contagio…
A form of psoriasis with multiple small, "raindrop-like" plaques, typical of young people and often following tonsillitis.…
A rare chronic infection causing patches with loss of sensation.…
A very common viral infection causing clusters of small, painful blisters — on the lip ("cold sores") or in other areas — reactivated by fever, sun or…
A chronic inflammatory disease with painful lumps and recurrent abscesses in the armpits, groin and buttocks.…
A chronic inflammatory disease of the hair follicles in skin folds — armpits, groin, buttocks — with painful lumps, abscesses and tunnels that recur i…
A firm brownish nodule, typically on the legs, which "dimples" when squeezed.…
A rare photodermatosis of childhood: blisters on sun-exposed areas that heal leaving small scars.…
A corticosteroid used as a marker for allergy to topical corticosteroids themselves — rare but deceptive.…
A small translucent cyst of the sweat glands, typically found on the eyelids.…
An acrylate found in gel nails and adhesives — the «gel nail allergy», affecting both clients and professionals.…
Excessive sweating, beyond what is needed to regulate temperature — most often in the armpits, palms of the hands and soles of the feet. It has a real…
Any area of skin darker than usual — from the sun, previous inflammation or present from birth.…
An exuberant actinic keratosis, with a hard projection of keratin shaped like a 'horn'.…
A raised, reddish scar that remains confined to the original wound (unlike a keloid).…
An area of lighter skin — pityriasis alba, pityriasis versicolor, naevus achromicus or early vitiligo.…
Dry skin with fine "fish-scale" flaking, particularly on the legs — the most common of the ichthyoses, often associated with atopy.…
Another formaldehyde-releasing preservative, common in cosmetics.…
A highly contagious superficial bacterial infection in children: sores with honey-coloured crusts, around the nose and mouth.…
A rare genetic condition with skin lesions that progress through phases (blisters, warty lesions, 'swirled' pigmentation) from birth onwards.…
The most common benign vascular tumour in babies: it appears in the first few weeks, grows for some months and then slowly regresses over a number of …
An injection of a small amount of corticosteroid directly into the lesion — for keloids, alopecia areata and hypertrophic scars, among other indicatio…
The most aggressive skin cancer, arising from melanocytes. The warning signs: asymmetry, irregular borders, several colours, growth (the ABCDE rule).…
The second most common skin cancer, linked to accumulated sun exposure: a nodule or sore that grows and does not heal.…
A benign tumour of the hair follicle: a solitary keratotic papule, usually on the face in adults.…
A preservative used in cosmetics and industrial products.…
Intense pulsed light: emits flashes of light that treat diffuse redness, small vessels, sun spots and photoageing, and is also used for light-based ha…
An antioxidant found in industrial black rubber — tyres, hoses, boots.…
This results from direct, repeated damage to the skin by irritants — detergents, disinfectants, excessive soap and water. It is very common on the han…
A vascular tumour associated with human herpesvirus 8, with purplish patches and nodules — classic forms in older people and forms associated with imm…
A preservative used in 'rinse-off' cosmetics and wipes, responsible for many recent outbreaks of allergy.…
A very rapidly growing tumour, shaped like a 'crater' with a horny centre, closely related to squamous cell carcinoma.…
"Chicken skin": small rough papules on the arms and thighs, very common and harmless.…
Derivatives of lanolin (wool fat) found in creams and ointments.…
An itchy, winding track that "walks" across the skin — a parasite picked up on tropical beach sand.…
Small, flat, well-defined brown patches, either sun-related or constitutional.…
A flat, stable brown patch — solar or simple.…
An autoimmune inflammatory disease of the hair follicles that causes patchy scarring alopecia, with redness and scaling around the hairs.…
An inflammatory condition causing shiny, violet-coloured, itchy papules on the wrists, ankles and mucous membranes.…
A chronic inflammatory condition with pearly white plaques, most often in the genital area, and also seen in children.…
A line of small papules appearing along a child's arm or leg, following the skin's natural lines.…
A rare autoimmune blistering disease of childhood, with tense blisters in a typical "string of pearls" arrangement.…
The most common benign tumour: a soft lump of fat beneath the skin.…
A brown or black band running along the nail. In children it is almost always benign, but it does require dermoscopic assessment.…
A childhood condition in which the hair comes away painlessly because it is poorly anchored — hair that «doesn't grow» and falls out easily.…
A variant of cutaneous lupus with smooth raised plaques, without scaling, which are photosensitive.…
A lymphatic malformation with clustered blisters resembling 'frogspawn'.…
A highly sensitising synthetic fragrance, now banned in new cosmetics in the EU.…
Melanoma at its earliest stage, confined to the epidermis — usually an irregular brown patch that changes slowly.…
A single brownish lesion, made up of mast cells, typical of babies — it may come up in a weal when rubbed.…
The definitive treatment for recurrent ingrowing toenails: the portion of the nail matrix responsible for the ingrowing nail fragment is removed (part…
The three "levels" of the common mole, according to the depth of the nests of melanocytes — from flat and dark (junctional) to raised and pale (intrad…
A group of rubber accelerators related to mercaptobenzothiazole.…
A rubber vulcanisation accelerator — gloves, footwear, elastics.…
A preservative from the Kathon family, used on its own, and also present in wall paints.…
Localised loss of elastic fibres with fine wrinkling of areas of the skin; rare and benign.…
Small, superficial white cysts filled with keratin, common on the face in newborns and adults.…
Small pearly "bumps" with a central dimple, caused by a virus — very common in school-age children and spread by contact.…
Also known as localised scleroderma: patches of hardened, pearly skin, without involvement of the internal organs.…
Removal of a fragment of mucosa (mouth, genital area) under local anaesthetic, for histological study of persistent lesions in these areas.…
Removal of a small fragment of muscle, under local anaesthetic, when investigating inflammatory diseases that affect the skin and muscle together.…
A stable pale patch present from birth or early childhood — a "birthmark" without pigment.…
A pale patch caused by a reduced response of the blood vessels — it disappears when the surrounding skin is pressed, unlike patches that lack pigment.…
Clustered soft, skin-coloured papules caused by fatty tissue in the dermis — typically over the lower back or buttocks.…
Taking a small piece of the nail or nail bed to clarify persistent changes — discolouration, deformity, suspected nail tumour.…
Reparative surgery of the folds that frame the nail, following tumours, injuries or deformities — restoring both anatomy and function.…
Psoriasis of the nails: pitting, "oil drop" patches, separation of the nail from the nail bed. It can occur without any visible skin psoriasis.…
A laser that reaches greater depth, used for larger vessels, certain vascular lesions and for safe hair removal in darker skin types.…
Rare, firm yellowish plaques around the eyes (periorbital), associated with gammopathies.…
A classic topical antibiotic — sensitisation is common with repeated use on wounds.…
A benign tumour of the nerve sheath: a soft, skin-coloured papule or nodule that can be "pushed in" with pressure. A single one is common and harmless…
A genetic condition that shows on the skin as multiple café-au-lait patches, freckling in the skin folds and neurofibromas.…
The most common contact allergen: costume jewellery, buckles, metal buttons, glasses.…
Excoriated nodules with intense itching, kept going by the scratch–thicken cycle.…
A group of rare conditions in which histiocytic cells accumulate in the skin, usually benign and self-limiting in children (such as juvenile xanthogra…
Round, 'coin-shaped' patches of eczema, with itching, most common on the legs and arms and associated with dry skin.…
A general term for nails that grow abnormally — thickened, brittle or misshapen — with many possible causes, from fungal infection to trauma and psori…
A naevus containing adnexal (sebaceous) components, closely related to the sebaceous naevus.…
Chondrodermatitis nodularis: a small, painful nodule on the rim of the ear, on the side you sleep on.…
Thickening of the skin of the palms and/or soles, either inherited or acquired.…
Inflammation of the subcutaneous fat with deep, painful nodules — erythema nodosum being the classic example.…
A contact adhesive used in footwear and leather goods.…
Classic preservatives — in fact among the least sensitising, but tested to clarify any suspicion.…
The dye found in dark hair colourants and in seaside "black henna" tattoos — it causes intense eczema of the scalp and hairline.…
A group of uncommon conditions that appear as persistent pink, scaly patches, usually on the trunk. Despite the name, it is distinct from psoriasis.…
The gold-standard laser for vascular lesions: rosacea, small facial vessels, angiomas and port-wine stains.…
A serious autoimmune blistering disease with erosions of the mouth and skin caused by intraepidermal separation.…
Small red papules around the mouth, nose or eyes, often made worse by creams containing corticosteroids.…
A small fibrous tumour beside the nail; multiple periungual fibromas (Koenen tumours) suggest tuberous sclerosis.…
Brownish patches with "cayenne pepper" spots on the legs, caused by benign capillary fragility.…
A benign tumour of the hair follicle, hard «as a stone» under the skin, common in children.…
A cyst in the cleft between the buttocks containing ingrown hairs, which readily forms an abscess in young people.…
An inflammatory condition with small scaly papules that appear in prolonged flare-ups in children and young people.…
A self-limiting rash: it begins with an oval «herald patch» and spreads across the trunk in a «Christmas tree» pattern.…
A very common superficial infection caused by a fungus that naturally lives on the skin (Malassezia). It causes lighter or darker patches with fine sc…
Ring-shaped plaques with a characteristic fine raised border («a wall»), occurring in several clinical forms.…
A capillary malformation present at birth: a dark red patch that persists and may thicken over the years.…
Dark marks left behind after inflammation of the skin (acne, eczema, insect bites) — more common in darker skin tones.…
Chromium found in cement and tanned leather — a classic cause of occupational eczema in construction workers and from footwear.…
This is the medical term for itching. When it persists, it is a symptom — not a disease — and may originate in the skin (dryness, eczema, urticaria) o…
A genetic disorder of the elastic fibres: yellowish, "plucked chicken skin" papules in the folds of the neck.…
A chronic, immune-mediated inflammatory disease that appears as red plaques with whitish scaling — typically on the elbows, knees and scalp. It is not…
A painful, rapidly growing ulcer with a violaceous border, caused by an autoinflammatory mechanism — it is associated with bowel and blood disorders.…
A benign, rapidly growing vascular lesion that bleeds easily — common after minor injuries, in pregnancy and in children.…
A formaldehyde-releasing preservative found in shampoos and creams.…
A heavily pigmented, almost black mole that grows rapidly, typically on the legs of young women — alarming to look at, benign under the microscope.…
A firm subcutaneous nodule over bony prominences in patients with rheumatoid arthritis.…
A chronic condition affecting the skin of the face: persistent redness, episodes of flushing, small visible vessels and, at times, spots. Certain trig…
A systemic granulomatous disease with skin involvement in the form of papules and plaques — sometimes the skin provides the first clue.…
An infestation by a mite that burrows tunnels in the skin, causing intense itching that is worse at night — it is passed on through close contact.…
A very common site for psoriasis: thick, scaly plaques, sometimes itchy, which may extend beyond the hairline.…
Scars result from the skin repairing itself after injury, acne or surgery; stretch marks result from rapid stretching of the skin (growth spurts, preg…
A small benign tumour of the sebaceous glands, yellowish, on the face.…
Small yellowish umbilicated papules on the face in adults, caused by enlarged sebaceous glands.…
A yellowish, hairless plaque on a baby's scalp, which thickens at puberty.…
Chronic inflammation of the areas with the most sebaceous glands — scalp, eyebrows, sides of the nose, chest. It causes redness and scaling ("dandruff…
A very common benign lesion from middle age onwards: a brown plaque that looks "stuck on" to the skin, with a dull surface — there is the common form …
A localised form of neurofibromatosis, limited to one segment of the body, caused by a mosaic mutation.…
Allergens from Compositae plants (chrysanthemums, daisies) — "airborne" eczema related to gardening.…
Removal of a small fragment of skin, under local anaesthetic, for examination under the microscope. It is the test that confirms the diagnosis when cl…
The «papillomas» of the neck and armpits: small, stalked pouches of skin, and very common.…
A pink or reddish, rapidly growing mole in children, which mimics melanoma under the microscope.…
An early form of squamous cell carcinoma, still confined to the epidermis — a persistent red, scaly patch on sun-exposed areas.…
Eczema of the legs associated with poor venous circulation, with brownish, fragile skin.…
An intermediate stage of eczema: redness and scaling with some weeping.…
A form of cutaneous lupus with ring-shaped or scaly lesions on sun-exposed areas, which is strongly photosensitive.…
A mole surrounded by a white, depigmented halo — the immune system "erasing" the naevus, a phenomenon that is generally benign in young people.…
An acute neutrophilic dermatosis: painful plaques and fever, sometimes associated with infections, medicines or blood disorders.…
A bacterial sexually transmitted infection with distinct stages: the initial painless sore (chancre), the secondary stage with a rash on the body and …
A rare benign adnexal tumour, often arising on a sebaceous naevus of the scalp.…
Small skin-coloured papules around the eyes, arising from the sweat glands — very common and benign.…
Small dilated vessels visible at the surface ("thread veins"), either isolated or associated with rosacea and other conditions.…
Increased, diffuse hair loss occurring weeks to months after a 'trigger' — fever, surgery, childbirth, restrictive diets, intense stress or certain me…
Another family of rubber accelerators — the leading cause of glove allergy.…
Infections caused by dermatophyte fungi — of the skin, hands, feet ("athlete's foot"), nails or scalp, the latter typical in children and potentially …
Dull, rough nails that feel «like sandpaper», sometimes affecting all twenty of a child's nails.…
Flaps that 'jump' over healthy skin to cover the defect — with one, two or three lobes depending on what is needed; the glabellar flap uses the skin b…
A thick-walled cyst of the scalp, often multiple and familial.…
A benign tumour of the hair follicle on the face; multiple forms are hereditary.…
A compulsive habit of pulling or plucking out one's own hair, creating areas of thinning with broken hairs of differing lengths — most common in child…
A genetic condition with characteristic skin signs (pale patches, facial angiofibromas, nail fibromas) that help with early diagnosis.…
A flap whose pedicle passes beneath a bridge of intact skin to reach the defect — avoiding additional scars on the surface.…
Straw-blond, dry and unruly hair that is impossible to comb, due to a structural change in the hair shaft — «pili trianguli et canaliculi».…
Inflammation of the urethra, usually due to a sexually transmitted infection (gonococcus, chlamydia), with burning on passing urine and discharge.…
A soft bluish papule on the lip or ear in older people — a small "lake" of venous blood.…
Surgical removal of the vermilion of the lip (the red area), indicated for extensive pre-malignant changes in this area, such as advanced actinic chei…
A rough, brown, linear lesion that follows the skin's developmental lines, present from an early age.…
Infection of the liver by a virus (B and C in the sexually transmissible forms) which may go on for years without symptoms.…
A wart caused by HPV located on the scalp, sometimes irritated by combing.…
Benign lesions caused by the human papillomavirus (HPV), common on the hands and feet (plantar warts, or “verrucas”). They are contagious through dire…
An autoimmune condition in which the skin loses its melanocytes (the pigment cells), forming well-defined white patches. It is neither contagious nor …
Yellowish deposits of lipids in the skin — on the eyelids (xanthelasma) or tendons — sometimes a sign of dyslipidaemia.…
A benign chronic inflammation of the glans in uncircumcised men, with a persistent red, shiny patch.…