EBDVD key terms

Pinpoint bleeding that appears when the scale of a psoriasis plaque is removed. It reflects thinning of the epidermis over elongated dermal papillae and is a classic, though not specific, bedside clue to psoriasis.

The appearance of new lesions of a skin disease along a line of trauma to previously unaffected skin, classically in psoriasis, lichen planus and vitiligo. It is also called the isomorphic response.

A composite score combining the extent of involved body surface with redness, thickness and scale, weighted by body region. It is used to grade severity and to monitor treatment response.

Fine, white, lacy lines visible on the surface of lichen planus papules, especially on mucosa and flexural skin. They correspond to focal hypergranulosis and are best seen with magnification or dermoscopy.

An acute eruption of target lesions with three concentric zones, usually triggered by herpes simplex infection. It mainly affects the extremities and mucosa and is distinct from drug-induced Stevens-Johnson syndrome.

A short, wavy, greyish track in the stratum corneum where the female Sarcoptes scabiei mite lays eggs. Found in web spaces, wrists and genitalia, it confirms the diagnosis and is best seen with dermatoscopy or ink.

The painless, indurated ulcer with a clean base and raised edges that marks primary syphilis at the site of Treponema pallidum inoculation. It heals spontaneously within weeks and is highly infectious.

A sexually transmitted genital ulcer disease caused by Haemophilus ducreyi, producing painful, soft ulcers with ragged edges and tender inguinal lymphadenitis. It is a key differential of the syphilitic chancre.

A poxvirus infection causing small, umbilicated, flesh-coloured papules, common in children and in immunosuppressed adults. Lesions resolve spontaneously but can become widespread in advanced HIV infection.

The vertical depth in millimetres from the granular layer of the epidermis to the deepest melanoma cell. It is the strongest single prognostic factor in cutaneous melanoma and guides staging and node discussion.

A staging procedure in which the first draining node is identified with dye or radiotracer and removed for histology. It detects micrometastasis in melanoma without removing the whole nodal basin.

Pigmentation extending onto the proximal nail fold from a pigmented nail lesion, suggesting subungual melanoma. Any new or changing longitudinal nail band with this sign warrants urgent nail matrix biopsy.

The most common cutaneous T-cell lymphoma, evolving through patches, plaques and tumours with a band-like dermal lymphocytic infiltrate and epidermotropism. Early disease mimics eczema and is often diagnosed after years.

A locally destructive, rarely metastasising keratinocyte tumour with pearly rolled edges, telangiectasia and sometimes ulceration, typically on sun-exposed skin. Diagnosis is clinical and dermoscopic; treatment is usually surgical.

Intercellular oedema of the epidermis that widens the spaces between keratinocytes and stretches desmosomes, giving a spongy appearance. It is the histological hallmark of eczematous dermatitis and correlates with visible vesicles.

Loss of adhesion between keratinocytes leading to rounded, detached cells and clefts or blisters within the epidermis. It is seen in pemphigus vulgaris, Hailey-Hailey disease and viral infections such as herpes.

A small collection of neutrophils in the stratum corneum, a characteristic histological finding in psoriasis. It corresponds clinically to the silvery scale and helps distinguish psoriasis from eczema on biopsy.

A technique using fluorescein-labelled antibodies on patient skin to detect deposited immunoglobulins and complement along the basement membrane or between keratinocytes. It is decisive in bullous diseases such as pemphigus and pemphigoid.

Magnified, usually polarised, examination of skin structures below the stratum corneum, revealing pigment networks, vessels and globules invisible to the naked eye. It improves diagnostic accuracy for pigmented and non-pigmented lesions.

Examination of skin, hair or nail material in potassium hydroxide solution, which dissolves keratin and leaves fungal hyphae, spores or mites visible. It is a rapid, inexpensive bedside test for dermatophytosis and scabies.

Excision of skin cancer with en-face frozen-section control of the entire surgical margin, performed in staged passes. It offers the highest cure rate with maximal tissue sparing, especially for facial basal cell carcinoma.

Local tissue destruction by freezing, usually with liquid nitrogen, used for warts, actinic keratoses and small benign lesions. Depth depends on freeze time and thaw cycles; pigment change and scarring are recognised risks.

Treatment in which a photosensitiser, usually a topical porphyrin precursor, is activated by light to destroy dysplastic cells and vessels. It is used for actinic keratoses, Bowen disease and superficial basal cell carcinoma.

Whealing and erythema provoked by rubbing or stroking a lesion of cutaneous mastocytosis, caused by mast cell degranulation. It is a useful bedside test in urticaria pigmentosa, especially in children.

An autosomal dominant disorder caused by NF1 mutations, diagnosed by café-au-lait macules, axillary freckling, neurofibromas, Lisch nodules and specific tumours. Cutaneous clues usually allow diagnosis in childhood.

A group of inherited disorders with mutations in structural skin proteins, causing blisters after minor mechanical trauma. Subtypes differ in cleavage level and extracutaneous involvement; care focuses on wounds and complication surveillance.

A standardised procedure applying allergens under occlusion to intact skin for 48 hours, with readings at 48 to 96 hours. It identifies delayed-type hypersensitivity causing allergic contact dermatitis.

A patch test in which duplicate allergen series are applied and, after removal, one set is irradiated with ultraviolet A while the other is shielded. It diagnoses photoallergic contact dermatitis.

Skin inflammation caused or aggravated by workplace exposures, most often irritant and affecting the hands. Diagnosis requires a careful work history, patch testing and sometimes workplace visits to confirm causation.

Separation of the epidermis from underlying skin when lateral pressure is applied to intact or eroded skin. A positive sign suggests intraepidermal blistering such as pemphigus vulgaris or toxic epidermal necrolysis.

An idiopathic inflammatory myopathy with characteristic skin signs: violet periorbital erythema, Gottron papules, shawl sign and nail-fold capillary changes. In adults it warrants screening for underlying malignancy.

Autoantibodies directed against nuclear antigens, detected by immunofluorescence on cultured cells. Titre and pattern, together with specific antibodies such as anti-dsDNA, support diagnosis and monitoring of connective tissue diseases.

A classification from I to VI based on tendency to burn and ability to tan after sun exposure. It guides photoprotection advice, laser settings and risk counselling for skin cancer and phototherapy.

The smallest dose of ultraviolet radiation that produces a just-perceptible erythema 24 hours after exposure. It is measured in phototesting to guide phototherapy dosing and to document photosensitivity.

The ratio of time to sunburn with sunscreen applied at 2 mg per square centimetre compared with unprotected skin, mainly reflecting UVB protection. Real-world protection is lower because people apply far less than the test dose.

The principle that a laser wavelength absorbed by a specific chromophore, delivered in a pulse shorter than the target's cooling time, destroys that target while sparing surrounding tissue. It underpins laser treatment of vessels, pigment and hair.

The process of explaining a proposed procedure's purpose, alternatives, risks and benefits so that the patient can decide freely. It requires documented capacity and discussion, not merely a signed form.

Systematically developed recommendations that help clinicians and patients make decisions about appropriate care in specific circumstances. Guidelines should be appraised for methodology, currency and applicability before adoption.

Delivery of dermatological consultation through store-and-forward images or live video, useful where specialist access is limited. It improves triage and access but carries risks of image quality, consent and diagnostic error.