Introduction
Clinical pattern | Dermatoses presenting with erythematous-desquamative patches plaques (I) | Dermatoses presenting with erythematous-desquamative patches plaques (II) | Papulosquamous—papulokeratotic dermatoses (I) | Papulosquamous—papulokeratotic dermatoses (II) |
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Dermoscopic clues of each dermatosis |
Plaque psoriasis:
• White scales • Symmetrically and regularly distributed, dotted vessels on a light or dull red background
Eczematous dermatitis:
• Yellow serocrustsa
• Dotted vessels in a patchy distributionb
Pityriasis rosea:
• Peripheral whitish scales (“collarette” sign) • Irregular or patchy dotted vessels |
Mycosis fangoides:
• Orange-yellowish patchy areas • Linear vessels with or without red dots forming peculiar “spermatozoon-like” structures
Subacute cutaneous lupus erythematosus:
• Whitish scale • Mixed vascular pattern (at least two types among dotted, linear-irregular, linear and branching vessels) |
Lichen planus:
• Wickham striae
Papulosquamous sarcoidosis:
• See “Facial inflammatory skin diseases (II)”
Pityriasis rosea:
• See “Dermatoses presenting with erythematous-desquamative patches plaques (I)” |
Guttate psoriasis:
• Diffusely distributed dotted vessels
Pityriasis lichenoides chronica:
• Nondotted vessels • Focally distributed dotted vessels • Orange-yellowish structureless areas
Classic pityriasis rubra pilaris:
• Round/oval yellowish areas surrounded by linear dotted vessels • Central keratin plugs |
Clinical pattern | Papulosquamous—papulokeratotic dermatoses (III) | Papulosquamous—papulokeratotic dermatoses (IV) | Facial inflammatory skin diseases (I) | Facial inflammatory skin diseases (II) |
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Dermoscopic clues of each dermatosis |
Disseminated forms of porokeratosis:
• Peripheral “cornoid lamella”
Lymphomatoid papulosis:
• Diffuse tortuous irregular (or dotted at low magnification) vessels (early lesions) • Central whitish-yellowish (hyperkeratotic lesions) or brown-grey (necrotic lesions) structureless area
Papulosquamous chronic GVHD:
• Whitish scales • Dotted and linear vessels |
Poikiloderma vasculare atrophicans:
• Sparse whitish scales • Blurred branched vessels on a reddish/orangish background
Grover disease, Darier disease and BRAF-inhibitor-induced acantholytic dyskeratosis:
• Central star-shaped/branched polygonal/roundish-oval brownish area surrounded by a whitish haloa
|
Rosacea:
• Linear vessels arranged in a polygonal network
Seborrheic dermatitis:
• Dotted vessels in a patchy distribution • Fine yellowish scales
Discoid lupus erythematosus:
• Perifollicular whitish halo (early lesions) • Follicular keratotic plugs, red dots (early lesions) • White scaling (early lesions) • Whitish structureless areas (late lesions) • Blurred linear branching (late lesions) |
Sarcoidosis, cutaneous leishmaniasis and lupus vulgaris:
• Diffuse or localised, structureless, orange yellowish areas • Focussed linear or branching vessels
Granuloma faciale:
• Dilated follicular openings • Linear branching vessels
Demodicidosis:
• “Demodex tails”b
• “Demodex follicular openings”b
|
Clinical pattern | Acquired keratodermas (I) | Acquired keratodermas (II) | Sclero-atrophic dermatoses | Hypopigmented macular diseases (I) |
---|---|---|---|---|
Dermoscopic clues of each dermatosis |
Palmar psoriasis:
• Diffuse white scaling
Chronic hand eczema:
• Brownish-orange dots/globules • Yellowish scales/crusts
Keratoderma due to mycosis fungoides:
• Relatively large, amber scales over a white-to-pinkish background
Keratoderma due to pityriasis rubra pilaris:
• Patchily distributed, homogeneous, structureless, orange areas |
Tinea manuum:
• Whitish scales mainly localised in the creases
Palmar lichen planus:
• Roundish, yellowish areas often having peripheral projections
Aquagenic palmar keratoderma:
• Yellowish-whitish well-defined globules • Enlargement of the sweat duct pores |
Morphea:
• Fibrotic beams
Lichen sclerosus:
• “Comedo-like openings” • Whitish patches
Necrobiosis lipoidica:
• Yellowish-orange/whitish-pinkish background • Comma-shaped (incipient lesions), network-shaped/hairpin-like (more developed lesions), or elongated, branching and focussed serpentine (advanced lesions) vessels |
Extragenital guttate lichen sclerosus:
• See “Sclero-atrophic dermatoses”
Achromic pityriasis versicolor:
• Fairly demarcated white area. Fine scales in the skin furrows
Guttate vitiligo:
• Well-demarcated, dense/glowing, white area • Perifollicular hyperpigmentation |
Clinical pattern | Hypopigmented macular diseases (II) | Hyperpigmented maculopapular diseases (I) | Hyperpigmented maculopapular diseases (II) | Hyperpigmented maculopapular diseases (III) |
---|---|---|---|---|
Dermoscopic clues of each dermatosis |
Idiopathic guttate hypomelanosis:
• “Cloudy sky-like” or “cloudy” patterna
Progressive macular hypomelanosis:
• Ill-defined whitish area without scaling
Postinflammatory hypopigmentation:
• Dermoscopic findings typical of the original lesions |
Pityriasis versicolor:
• Fine whitish scaling • Pigmented network composed of brown stripes/diffuse brownish pigmentation
Lichen planus pigmentosus:
• Diffuse, structureless, brownish pigmentation • Fine/coarse, grey-blue/brown dots/globules
Confluent and reticulated papillomatosis (Gougerot-Carteaud syndrome):
• Fine whitish scaling • Brownish areas in a “cobblestone” or “sulci and gyri” pattern |
Dowling-Degos disease:
• Brown star-like area/irregular brownish projections with a hypopigmented centre
Erythema ab igne (hyperpigmented stage):
• Diffuse brownish pigmentation • Telangiectatic vessels • Whitish scaling
Macular amyloidosis and lichen amyloidosus:
• White or brown central hub surrounded by various configurations of brownish pigmentationb
|
Friction melanosis:
• Brownish structureless areas arranged in a reticular fashion
Terra firma-forme dermatosis:
• Large polygonal plate-like brown scales arranged in a mosaic pattern
Urticaria pigmentosa:
• Homogeneous light-brown blot and/or pigment network
Telangiectasia macularis eruptiva perstans:
• Reticular vessels on a erythematous or brownish base |
Clinical pattern | Itchy papulonodular dermatoses | Erythrodermas (I) | Erythrodermas (II) | Noninfectious balanitis—erythroplasia of Queyrat |
---|---|---|---|---|
Dermoscopic clues of each dermatosis |
Hypertrophic lichen planus:
• Rippled surface • “Comedo-like” structures • Round corneal structures (“corn pearls”)
Prurigo nodularis:
• “White starburst” patterna
Nodular scabies:
• Mites (“hang glider sign”) • Burrows (“jet with condensation trails”)
Acquired perforating dermatosis:
• Three concentric areas with different aspect/colour |
Erythrodermic psoriasis:
• Diffusely distributed whitish scales • Regularly arranged dotted/glomerular vessels
Erythrodermic atopic dermatitis:
• Yellowish scales/sero crusts • Patchily distributed dotted vessels
Erythrodermic mycosis fungoides:
• Linear vessels (including spermatozoon-like vessels) and dotted vessels |
Erythrodermic pityriasis rubra pilaris:
• Orange blotches • Islands of nonerythematous (spared) skin displaying reticular vessels
Erythrodermic scabies:
• Dark-brown triangular structures located at the end of whitish structureless wavy lines (delta-wing jets with contrail) |
Zoon’s plasma cell balanitis:
• Focal/diffuse orange-yellowish structureless areas • Fairly focussed curved vessels (including serpentine, convoluted and chalice-shaped)
Psoriatic balanitis:
• Regularly distributed dotted/glomerular vessels
Seborrheic dermatitis and non-specific balanitis:
• Linear irregular unspecific blurry vessels
Erythroplasia of Queyrat:
• Scattered glomerular vessels |
Clinical pattern | Inflammatory cicatricial alopecia | Nonscarring alopecias | Scaling disorders of the scalp |
---|---|---|---|
Dermoscopic clues of each dermatosis |
Discoid lupus erythematosus:
• Follicular keratonc plugs, thick arborising vessels and red dots (acute lesions) • Thin arborising vessels emerging from yellow dots (late lesions) • White areas and branching vessels (long-lasting lesions)
Lichen planopilaris:
• Perifollicular scales
Frontal fibrosing alopecia:
• Minor perifollicular scaling • Lonely hair/predominance of follicular openings with only one hair at the hair-bearing margin
Folliculitis decalvans:
• Follicular pustules • Yellow discharge/crusts • Hair tufts that contain >10 hairs Shafts |
Alopecia areata:
• Black dots, micro-exclamation mark hairs, broken hairs, tapered hairs, monilethrix-like hairs and trichorrhexis nodosa (acute forms) • Regular yellow dots (inactive lesions); • Circle and/or pigtail hairs (regrowing phases)
Trichotillomania:
• Hairs broken at different lengths • Short hairs with trichoptilosis (“split ends”) • Other: irregular coiled hairs, amorphous hair residues, black dots, flame-like hairs, tulip-like hairs and V-signa
Androgenetic alopecia:
• Hair shaft thickness heterogeneity • Increased proportion of thin and vellus hairs (>10 % of the hairs)
Telogen effluvium:
• Lack of features typical of other diseasesb
|
Tinea capitis:
• “Comma” hair, “corkscrew” hair, “zigzag” hair and “Morse code” hair
Scalp psoriasis:
• Red dots/globules • Signet ring vessels, red loops, white scales, punctate hemorrhages and hidden hairs (with a lower specificity)
Seborrheic dermatitis:
• Arborizing vessels • Yellowish scaling, structureless red areas, honeycomb pigment and comma vessels (with a lower specificity)
Pityriasis amiantacea:
• Compact white keratotic material adhering to a tuft of hair (asbestos-like scale) |