Erythroderma
A severe generalised skin condition characterised by redness and scaling affecting more than 90% of the body surface area.
Keloid
A fibroproliferative scar that extends beyond the original wound margins, arising from abnormal collagen synthesis.
Koebner Phenomenon
The development of skin lesions characteristic of a pre-existing dermatosis at sites of cutaneous trauma or injury.
Lentigines
Benign, flat, pigmented macules resulting from a localised increase in melanocyte number, which — unlike ephelides — do...
Lichenification
Thickening and hardening of the skin with exaggerated surface markings, resulting from repeated scratching or rubbing.
Melanocytic Naevus
A benign proliferation of melanocytes presenting as a pigmented skin lesion, commonly referred to as a mole, which may b...
Melanonychia
Longitudinal or diffuse brown-to-black pigmentation of the nail plate caused by melanin deposition, requiring careful di...
Milia
Small, keratin-filled epidermal cysts appearing as white or yellowish papules, most commonly around the eyes and on the...
Mohs Micrographic Surgery
A specialised surgical technique for skin cancer in which successive thin layers of tissue are excised and immediately e...
Morbilliform Rash
A widespread, blanchable, erythematous maculopapular eruption resembling the exanthem of measles, most commonly drug-ind...
Naevus
A circumscribed benign proliferation of melanocytes or other skin cells, commonly called a mole; the preferred British/i...
Narrowband UVB
A form of phototherapy using ultraviolet B radiation at a specific wavelength of 311–313 nm, used to treat inflammatory...
Nickel Sulphate
The standard reagent used in patch testing to assess contact sensitisation to nickel, the most prevalent contact allerge...
Nikolsky Sign
A clinical test result in which lateral pressure on apparently normal skin causes the epidermis to shear away, indicatin...
Nummular Eczema
A chronic dermatitis characterised by coin-shaped, well-demarcated plaques of eczematous skin, typically on the limbs.
Onychodynia
Pain localised to one or more nails or the periungual region, used as a symptom descriptor in nail disorder documentatio...
Onycholysis
The painless separation of the nail plate from the nail bed, beginning distally or laterally, seen in psoriasis, fungal...
Onychomycosis
A fungal infection of the nail unit, most commonly caused by dermatophytes, characterised by nail thickening, discoloura...
Panniculitis
Inflammation of the subcutaneous fat layer (panniculus adiposus), presenting clinically as tender subcutaneous nodules o...
Parakeratosis
A histological finding characterised by retention of nuclei in the stratum corneum, indicating abnormal keratinisation.
PASI
An acronym for Psoriasis Area and Severity Index, a validated scoring tool quantifying the extent and severity of psoria...
Patch Test
A standardised epicutaneous diagnostic procedure used to identify type IV (delayed) hypersensitivity reactions to contac...
Pemphigus Vulgaris
An autoimmune blistering disorder characterised by intraepidermal bullae caused by autoantibodies against desmoglein 3.
Perioral Dermatitis
A facial dermatosis characterised by papulopustular eruptions around the mouth (and sometimes the nose and eyes), freque...
Photoageing
Premature skin ageing caused by cumulative exposure to ultraviolet radiation, producing dyspigmentation, solar elastosis...