DR2.1,DR3.1-3,DR4.1 | Papulosquamous & Pigmentary Disorders — Glossary

A systemic retinoid particularly useful in pustular and erythrodermic psoriasis; strongly teratogenic, requiring prolonged contraception in women.

A skin patch with impaired sensation; in a hypopigmented lesion it strongly suggests leprosy and must be excluded in every pale patch.

Pinpoint bleeding points that appear after the scale is removed from a psoriatic plaque, due to dilated dermal papillary capillaries beneath a thinned epidermis.

A targeted systemic therapy blocking a specific cytokine (TNF-α, IL-17, or IL-23) in the psoriasis pathway; used for refractory moderate-severe disease.

An estimate of the proportion of skin affected, using the patient's palm as roughly 1%; <10% limited, 10–20% moderate, >20% severe psoriasis.

The eponymous name for the graded-scraping technique of the Grattage test, after the French dermatologist Louis Brocq.

An alternative name for the glistening last membrane of the Grattage test, seen after complete scale removal.

Topical tacrolimus or pimecrolimus, preferred for facial and flexural vitiligo and in children because it avoids steroid-induced atrophy.

A topical vitamin D3 analogue that normalises keratinocyte differentiation, used alone or with betamethasone in a fixed-dose combination.

Silvery-white scale that flakes off like shavings of candle wax when a psoriatic plaque is gently scraped, reflecting loose parakeratotic scale.

Acquired depigmentation from contact with chemicals, most often catechols in rubber and adhesives or topical monobenzyl ether of hydroquinone.

The commonest form of psoriasis (psoriasis vulgaris), with stable, symmetrical silvery-scaled plaques on extensor surfaces, scalp, and sacrum.

Apoptotic keratinocytes (also called colloid or hyaline bodies) seen at the dermoepidermal junction in lichen planus; demonstrable by direct immunofluorescence.

An anti-proliferative, anti-inflammatory topical agent; combined with UVB in the Goeckerman regimen.

A blunt scraping instrument acceptable for grattage; the blunt edge avoids the laceration that a scalpel blade would cause.

A calcineurin-inhibitor systemic agent giving rapid control; limited by nephrotoxicity and hypertension to short-term use.

Complete loss of melanin because the melanocytes themselves are absent; the basis of the milky-white colour of vitiligo.

Deliberate, irreversible removal of remaining normal pigment (using monobenzyl ether of hydroquinone) offered for very extensive vitiligo for cosmetic uniformity.

Finger-like upward projections of the dermis carrying capillaries; in psoriasis they are elongated with dilated tortuous vessels close to the surface.

A laboratory technique that, in lichen planus, shows globular cytoid bodies staining for IgM and C3 at the dermoepidermal junction.

Dermatology Life Quality Index — a ten-item questionnaire measuring the impact of skin disease on daily life; a score ≥10 indicates significant impairment.

A painful, raw, erosive oral form carrying a small (~1%) risk of malignant transformation and requiring long-term surveillance.

The most severe variant, with erythema and scaling involving more than 90% of body surface area, threatening thermoregulation and fluid balance.

A treatment combining topical coal tar with ultraviolet B phototherapy for plaque psoriasis.

A bedside procedure (Brocq's method) in which a psoriatic plaque is scraped in a graded manner to elicit, in sequence, the candle-grease sign, the last membrane, and the Auspitz sign.

An acute eruption of small droplet-shaped scaly papules over the trunk, classically two to three weeks after a streptococcal throat infection.

The single larger initial lesion of pityriasis rosea, preceding the generalised eruption — a feature that distinguishes it from psoriasis.

The major histocompatibility allele most strongly associated with psoriasis, reflecting its immunogenetic basis.

Thickening of the granular layer of the epidermis; in lichen planus it underlies the Wickham striae.

A thick, warty, intensely itchy variant typically affecting the shins.

Reduced melanin with melanocytes still present; gives a duller, off-white appearance, as in leprosy, pityriasis versicolor, or pityriasis alba.

The central immune pathway in psoriasis, in which dendritic cells and Th17 lymphocytes drive cytokines that cause keratinocyte hyperproliferation.

An agent such as salicylic acid that removes thick scale, allowing active topical drugs to penetrate the plaque.

The appearance of new psoriatic (or lichen planus / vitiligo) lesions along sites of skin trauma such as scratches or scars; also called the isomorphic response.

Potassium hydroxide microscopy of skin scrapings used to demonstrate fungal hyphae and confirm or exclude tinea (dermatophyte) infection.

The thin, smooth, glistening film (terminal film or Büchner sign) revealed after the loose scale is fully removed, immediately before the Auspitz sign.

Infection by Mycobacterium leprae producing hypopigmented, anaesthetic patches, sometimes with thickened nerves; the critical differential of vitiligo in India.

A fixed white oral patch that cannot be wiped away and is itself premalignant; an important differential of oral lichen planus.

White hair within a vitiligo patch, indicating follicular melanocyte loss and predicting a poorer response to medical treatment.

Follicular lichen planus of the scalp causing perifollicular inflammation and permanent scarring (cicatricial) alopecia.

A common, itchy, T-cell-mediated papulosquamous disease affecting skin, mucosa, nails, and scalp, characterised by violaceous flat-topped papules and Wickham striae.

A drug-induced eruption clinically resembling lichen planus, caused by agents such as antimalarials, gold, thiazides, or beta-blockers, that resolves on withdrawal.

An inflammatory pattern in which cytotoxic T-cells attack basal keratinocytes at the dermoepidermal junction; the histological basis of lichen planus.

A folate-antagonist systemic agent for severe psoriasis; needs folic acid supplementation and FBC/LFT/renal monitoring, and is teratogenic.

A collection of neutrophils within the stratum corneum, a characteristic histological feature of psoriasis.

Small thumbprint-like depressions in the nail plate, a common and diagnostically useful nail change in psoriasis.

Phototherapy at 311–313 nm; the preferred first-line phototherapy for psoriasis, effective and safe in pregnancy as it uses no psoralen.

A congenital, stable, non-progressive hypopigmented patch present from birth, unrelated to autoimmunity.

The commonest, often symmetrical and progressive form, associated with autoimmunity.

Separation of the distal nail plate from the nail bed; in psoriasis it may accompany the orange-brown oil-drop sign.

A descriptive category of skin disorders characterised by papules and plaques surfaced by scale; includes psoriasis, lichen planus, pityriasis rosea, and others.

Retention of nuclei in the stratum corneum due to accelerated, incomplete keratinocyte maturation; the histological basis of psoriatic scale.

Psoriasis Area and Severity Index — a composite score of erythema, induration, scaling, and area; mild <10, moderate 10–20, severe >20.

Poorly defined hypopigmented, finely scaly patches on the face of atopic children; not depigmented and self-limiting.

A Malassezia fungal infection giving scaly hypo- or hyperpigmented macules; KOH-positive with golden-yellow Wood's lamp fluorescence.

A raised, well-demarcated, flat-topped skin lesion larger than 1 cm; the typical primary lesion of chronic plaque psoriasis.

The well-demarcated, silvery-scaled, erythematous lesion of psoriasis on which the Grattage test is performed.

Scarring that fuses the proximal nail fold to the nail bed; a pathognomonic nail change of lichen planus.

A psoriasis variant defined by sterile pustules, either localised (palmoplantar) or generalised (the febrile, dangerous Von Zumbusch pattern).

Psoralen plus UVA phototherapy; reserved for resistant cases because cumulative exposure raises long-term skin-cancer risk.

The worsening of psoriasis into a generalised pustular or erythrodermic form following withdrawal of systemic corticosteroids — the reason they are contraindicated.

The commonest oral form — a bilateral lacy white network on the buccal mucosa, usually asymptomatic.

An irregular, jagged acanthosis of the epidermal rete ridges characteristic of lichen planus histology.

An erythematosquamous condition with greasy yellow scale on seborrhoeic sites; gives a negative Grattage test, a key differential.

Vitiligo confined to one region, typically of early onset, which characteristically stabilises quickly.

The thin layer of epidermis (only 2–3 cells thick in psoriasis) overlying the dermal papillae, whose thinning allows the Auspitz sign.

A topical calcineurin inhibitor preferred for oral, genital, and facial lichen planus because it avoids the atrophy caused by prolonged topical steroids.

Another term for the last membrane — the glistening surface seen after scale removal in the Grattage test.

First-line topical agent for limited plaque psoriasis; potency is selected by body site to balance efficacy against skin atrophy.

Bleeding caused by laceration from a sharp instrument or over-vigorous scraping, which can be mistaken for a true Auspitz sign.

An autoimmune disorder in which melanocytes are destroyed, producing sharply defined milky-white depigmented macules and patches.

Acute generalised pustular psoriasis with fever and systemic upset; a dermatological emergency requiring inpatient care.

Fine white lacy lines on the surface of lichen planus papules; their presence (with absent Auspitz sign) helps distinguish lichen planus from psoriasis.

A long-wave ultraviolet lamp used in a dark room; vitiligo shows bright chalky blue-white accentuation, aiding diagnosis especially in fair skin.