Dermoscopy of inflammatory skin diseases
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|Author(s)||Sabine Ludwig · Aimilios Lallas · Iris Zalaudek|
|Responsible author||Aimilios Lallas → send e-mail|
|Status update||August 20, 2017|
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Cite:Dermoscopy of inflammatory skin diseases Message:Dermoscopy of inflammatory skin diseases Participate:Dermoscopy of inflammatory skin diseases
The basic principles of applying dermoscopy in inflammatory diseases are the following: 1. Interpretation of dermoscopic findings should be always context-driven. The diagnosis in dermatology is usually established on the basis of the clinical morphology and distribution of the skin eruption. Sometimes, the clinical manifestations do not allow the establishment of a definite diagnosis and more than 1 diseases are included in the differential diagnosis. Applying dermoscopy and interpreting dermoscopic findings makes sense only within this specific differential diagnosis that has been established clinically.
2. The main parameters that have to be evaluated when applying dermoscopy in general dermatology are the following: i) Vessels morphology ii) Vessels distribution iii) Scale color iv) Scale distribution v) Follicular criteria vi) Pigmented structures vii) Specific clues
3.The selection of equipment that preserves vessels’ morphology is essential because vascular structures represent the most important group of criteria in diagnosing inflammatory skin diseases. Evaluation of vascular structures should be performed with a second-generation hand-held dermatoscope using polarized light. If only a standard dermatoscope requiring direct contact is available, ultrasound gel and an examination with only applying minimal pressure may prevent the alteration or disappearance of vascular structures. Similar if acquiring a dermoscopic image, it is preferable to use new-generation dermatoscopes instead of contact-dermatoscopes for inflammatory lesions.
Psoriasis[edit | edit source]
Dotted vessels represent the most frequent dermoscopic feature of Psoriasis, being present in every single psoriatic plaque. Detection of any other morphologic type of vessels excludes the diagnosis of PP. The term “red globules” has also been used to describe the same dermoscopic feature.  Distinction between dots and globules is based on the diameter of the structure (dots are smaller), and it is important in dermoscopy of melanocytic tumors. In psoriasis, both terms may be used, since the roundish vascular structures can be of various diameters, although they are usually of similar size within a given lesion. Under higher magnifications (x100-x400), the psoriatic vessels appear as dilated, elongated, and convoluted capillaries. Histopathologically, red dots correspond to the loops of vertically arranged vessels within the elongated dermal papillae. Important for differential diagnosis, the uniform distribution of the red dots within the lesion represents the dermoscopic hallmark of psoriasis. Dotted vessels may be detected in several inflammatory dermatoses, but no other disease exhibits the symmetrical and homogenous arrangement of vessels all over the lesion that characterizes psoriatic plaques, unless thick superficial scales cover them. Scales removal will bring to light the characteristic vascular pattern of psoriasis, possibly together with tiny red blood drops, which can be characterized as the dermoscopic “Auspitz sign”. A specific feature for the diagnosis of psoriasis is the sign of red globular rings, described by Vazquez-Lopez et al. If present, the red globules are arranged in irregular circles or rings. But even if highly specific, this sign is only seen in a minority of psoriatic lesions. Other types of vessels distribution are extremely rare in psoriasis.  In addition, light red background color and white superficial scales are two common dermoscopic criteria of plaque psoriasis. In differential diagnosis of erythematosquamous dermatoses, scale color is of particular value: Yellow scales are a negative predictor of plaque psoriasis, therefore argueing for the presence of dermatitis.  Dermoscopic findings of psoriasis may vary dependent of the body site and the various amounts of scaling. In psoriatic balanitis and inverse psoriasis lesions that lack scaling, the regularly distributed red dots are prominent. Contrariwise, in scalp or palmoplantar psoriasis, thick hyperkeratotic plaques hide the typical vascular structures, which may be recognized after removal of the scales.
Dermoscopic transformation of psoriatic plaques under treatment[edit | edit source]
Regular dermoscopic examination is of avail in patients under treatment with topical steroids or systemic biological agents, because additional morphologic information might be helpful for early detection of a relapse. Additionally, steroid-induced skin atrophy is earlier detected by dermoscopy (by revealing characteristic linear vessels) than in the clinical setting.
Dermatitis[edit | edit source]
Despite their variable etiopathologies, all forms of dermatitis show similar histopathologic just as similar dermoscopic characteristics. Dermatitis usually exhibits red dots in a patchy distribution and yellow scales. The red dots are identical to the vessels in psoriatic lesions, but unlike psoriasis, their distribution is not homogenous and regular, but rather clustered, generating an irregular, “patchy” pattern.
Superficial scaling is a frequent characteristic of dermatitis, but opposed to psoriasis and other erythematosquamous skin diseases, the scales in dermoscopy of dermatitis reveal a yellow color either alone, or in combination with white.  Belonging to the group of the characteristic yellow scales, the “yellow clod sign” is frequently observed in nummular eczema. Notably, yellow scale color is dermoscopically detected not only in acute, but also in chronic dermatitis. Contact dermatitis, nummular eczema, generalized dermatitis, chronic dermatitis, seborrheic dermatitis and other subtypes were reported to reveal similar findings in dermoscopy, but further investigation on their specific pattern is needed.
Lichen planus[edit | edit source]
White crossing streaks (Wickham striae) are the hallmark of lichen planus not only in clinical examination (particularly in mucous lesions), but also in dermoscopy. White crossing streaks are a specific, as well as a constant finding for lichen planus, irrespectively of lesion’s duration or subtype. Vessels of mixed morphology (dotted and linear) may be found at the periphery of the lesion.
Pityriasis rosea[edit | edit source]
The two major dermoscopic features of pityriasis rosea are yellowish background color and peripheral whitish scales. Besides, dotted vessels may be detected in dermoscopy of most pytiriasis rosea lesions, as seen in psoriasis and dermatitis. However, the vascular pattern lacks the characteristic regular distribution of psoriasis. 
Pityriasis rubra pilaris[edit | edit source]
Whitish keratotic plugs and linear vessels either solely or mixed with dotted vessels on a yellowish background are the most frequent dermoscopic features reported for pityriasis rubra pilaris. This observation suggests that pityriasis rubra pilaris shows no typical characteristics of psoriasis, which is the most common differential diagnosis.   
Porokeratosis[edit | edit source]
In porokeratosis, the cornoid lamella, known as the histopathologic hallmark of porokeratosis, is revealed by dermoscopic examination as a well-defined, white-yellowish peripheral annular structure (“white track”, ‘‘the outlines of a volcanic crater as observed from a high point’’). In disseminated superficial actinic porokeratosis, the peripheral track may be hyperpigmented.  Depending on the disease subtype and the stage of progression, the central part of porokeratotic lesions can demonstrate a brownish pigmentation, dotted or linear vessels, or a structureless whitish area. By dermoscopy, the diagnosis of porokeratosis is performed without difficulty, even in clinically atypical cases.
Granulomatous skin diseases[edit | edit source]
In dermoscopy, the presence of orange-yellowish globules or areas and linear vessels are highly suggestive of dermal granulomas and therefore easily allows the diagnosis of granulomatous skin diseases. However, their differential diagnosis remains challenging due to identical dermoscopic presentation produced by several causes. Notably, the plaque form of cutaneous sarcoidosis may resemble necrobiosis lipoidica. The longer and more branching telangiectasias of necrobiosis lipoidica, caused by atrophic changes not present in cutaneous sarcoidosis, were reported to be an important feature for discrimination from other granulomatous diseases.
Sarcoidosis and lupus vulgaris[edit | edit source]
In sarcoidosis  and lupus vulgaris, orange-yellowish translucent globular-like or structureless areas in combination with linear vessels have been described, which are suggested to correspond to the underlying granulomas.
Cutaneous leishmaniasis[edit | edit source]
In cutaneous leishmaniasis, dermoscopy reveals generalized erythema, yellow tears (follicular plugs), hyperkeratosis and central erosion/ulceration. The characteristic translucent orange-yellowish color of sarcoidosis may additionally be present.
Granuloma annulare[edit | edit source]
Granuloma anulare may reveal a high variability of dermoscopic findings. Vessels may be dotted, short linear or linear arborizing, while background color displays various combinations of red, white and yellow. In certain cases, pigmented structures may be detected. The observation that granuloma anulare rarely exhibits features of other granulomatous skin diseases, such as necrobiosis lipoidica or sarcoidosis, might help clinicians rule out the latter conditions.
Necrobiosis lipoidica[edit | edit source]
Necrobiosis lipoidica exhibits a characteristic and repetitive pattern, typified by a prominent network of linear arborizing vessels and a yellow background color. The prominent vascular network of necrobiosis lipoidica represent the most valuable feature for differential diagnosis from other granulomatous diseases. This typical vascular morphology should be differentiated from the classical ‘arborizing' vessels of nodular-cystic basal cell carcinoma. Classical arborizing vessels usually reveal ramifications into finest capillaries, while vessels in necrobiosis lipoidica exhibit only few diameter variegations and reveal multiple anastomosing ramifications. Ulcerations and yellow crusts represent the most common additional features.
Discoid lupus erythematosus[edit | edit source]
Dermoscopic criterias differ depending on the stage of progression of discoid lupus erythematosus. In early lesions, perifollicular whitish halo, follicular plugging and white scales are the predominant features, while in longer-standing lesions telangiectatic vessels, pigmentation structures and whitish structureless areas prevail. This distinct dermoscopic pattern is useful for discriminating discoid lupus erythematosus from lupus pernio (cutaneous sarcoidosis) and lupus vulgaris (cutaneous tuberculosis). The latter diseases lack the predominant follicular abnormalities of discoid lupus erythematosus, and display a characteristic pattern consisting of orange-yellowish areas/globules and branching arborizing vessels.
Rosacea[edit | edit source]
Rosacea is characterized by a unique dermoscopic vascular pattern of polygonal vessels. Since this pattern of dermoscopic vascular polygons is not present in any other skin disease, this is a sensitive criterion for the diagnosis of rosacea. Regarding the accuracy in evaluation of vascular alterations by dermoscopy, the technique may be additionally useful for follow up of rosacea. Additional dermoscopic findings of rosacea include follicular plugs, white scales, features related to the presence of demodex (“demodex tails”) and whitish amorphic follicular material. However, the frequency of these additional criteria is relatively low. In papulopustular rosacea, clinically non-visible pustules provide a useful dermoscopic clue for discrimination from lupus erythematosus, but this requires further investigation.
Lichen sclerosus and morphea[edit | edit source]
The predominant dermoscopic feature of lichen sclerosus are white-yellowish structureless areas, independently of the location. Genital lichen sclerosus commonly appear with linear vessels while extragenital lesions rather exhibit keratotic plugs, surrounded by an erythematous halo. This halo represents a marker of disease activity.  In morphea, linear vessels within the lilac ring are a typical finding in dermoscopy. By dermoscopical examination, lichen sclerosus is typified by comedo-like openings and whitish patches, whereas morphea exhibits fibrotic beams.
Urticaria and urticarial vasculitis[edit | edit source]
Common urticaria is dermoscopically characterized by a red, reticular network of linear vessels, which may be surrounded by an area devoid of vessels, corresponding to dermal edema. On the contrary, urticarial vasculitis dermoscopically exhibit purpuric dots or globules on an orange-brown background. Both diseases reveal no highly specific criteria, but the presence of purpuric dots is suggestive of an underlying vasculitis.
Pigmented purpuric dermatoses[edit | edit source]
The term pigmented purpuric dermatoses comprehends the following entities: Schamberg’s disease, Majocchi purpura, eczematoid purpura of Doucas and Kapetanakis, lichen aureus and pigmented purpuric lichenoid dermatitis of Gougerot-Blum. Pigmented purpuric dermatoses are dermoscopically identified by the combination of purpuric dots or globules and orange-brown areas of pigmentation. A similar dermoscopic pattern has been described in patients with mycosis fungoides, supporting previous evidence reporting clinical and histopathologic overlap between the two entities. Since the pigmented purpuric dermatoses and mycosis fungoides notably differ in physical course and management, lesions showing a dermsocopic pattern of pigmented purpuric dermatoses should be evaluated carefully.
Darier’s disease[edit | edit source]
In Darier’s disease, dermoscopical analysis highlights the characteristic pseudocomedones and therefore is an effective additional tool for its clinical recognition. Vascular patterns are unspecific, comprising erythema, dotted and linear vessels.
Mastocytosis[edit | edit source]
For cutaneous mastocytosis four dermoscopic patterns have been defined: light-brown blot, pigment network, reticular vascular pattern, and yellow-orange blot.   Dermoscopic pattern varies depending on the subtype : In maculopapular mastocytosis, light-brown blot and pigment network predominate. In solitary mastocytoma, a yellow orange blot is typical. In all cases of telangiectasia macularis eruptiva perstans, a reticular vascular pattern is present. The reticular pattern of the vessels is even proved associated with an increased risk of need for daily use of anti-mediator medication. Therefore, dermoscopy in combination with other variables could provide additional help in the identification of patients at risk for more severe symptoms.
Vasculitides[edit | edit source]
Scarce evidence exists on the dermoscopic pattern of vasculitides. Henoch-Schonlein purpura has been shown to dermoscopically reveal irregularly shaped red patches with blurred borders. Reported findings of urticarial vasculitis are described above. In granuloma faciale, the specific dermoscopic features are dilated follicular openings, perifollicular whitish halo, follicular keratotic plugs and linear branching vessels. Clinically, granuloma faciale has to be differentiated from sarcoidosis, discoid lupus erythematosus, lupus vulgaris, lymphoma and basal cell carcinoma. The mentioned dermoscopic patterns simplify clinical differential diagnosis. But the distinction from discoid lupus erythematosus, which exhibits similar findings, remains challenging.
Mycosis fungoides[edit | edit source]
Even if being a neoplastic disease, mycosis fungoides is listed in this article as a major differential diagnosis from several inflammatory skin disorders. In particular, differentiation between chronic dermatitis and early stage mycosis fungoides is often highly problematic. In dermoscopical studies, significant differences have been shown: In contrast to the dotted vessels in dermatitis, mycosis fungoides reveal short linear vessels and orange-yellowish areas. In addition, in mycosis fungoides a peculiar vascular structure is frequently observed consisting of a dotted and a linear component (spermatozoon-like structure). In the assessment of a chronic lesion previously diagnosed as dermatitis, dermoscopic examination is expected to reveal dotted vessels, occasionally combined with yellowish scales. Lesions under long-term treatment with topical steroids represent the only exception to this rule. When, instead, dermoscopy reveals linear vessels, the suspicion of mycosis fungoides rises strongly and in this case, patient’s management should be adjusted accordingly.
- ↑ Zalaudek et al.: How to diagnose nonpigmented skin tumors: a review of vascular structures seen with dermoscopy: part II. Nonmelanocytic skin tumors. J. Am. Acad. Dermatol. 2010;63:377-86; quiz 387-8. PMID: 20708470. DOI.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Lallas et al.: Accuracy of dermoscopic criteria for the diagnosis of psoriasis, dermatitis, lichen planus and pityriasis rosea. Br. J. Dermatol. 2012;166:1198-205. PMID: 22296226. DOI.
- ↑ 3.0 3.1 Vázquez-López et al.: Dermoscopic features of plaque psoriasis and lichen planus: new observations. Dermatology (Basel) 2003;207:151-6. PMID: 12920364. DOI.
- ↑ De Angelis et al.: Videocapillaroscopic findings in the microcirculation of the psoriatic plaque. Dermatology (Basel) 2002;204:236-9. PMID: 12037454. DOI.
- ↑ Vázquez-López et al.: A dermoscopy subpattern of plaque-type psoriasis: red globular rings. Arch Dermatol 2007;143:1612. PMID: 18087028. DOI.
- ↑ Kim et al.: Dermoscopy can be useful in differentiating scalp psoriasis from seborrhoeic dermatitis. Br. J. Dermatol. 2011;164:652-6. PMID: 21155753. DOI.
- ↑ Vázquez-López & Marghoob: Dermoscopic assessment of long-term topical therapies with potent steroids in chronic psoriasis. J. Am. Acad. Dermatol. 2004;51:811-3. PMID: 15523365. DOI.
- ↑ Navarini et al.: The yellow clod sign. Arch Dermatol 2011;147:1350. PMID: 22106141. DOI.
- ↑ 9.0 9.1 Vázquez-López et al.: Dermoscopic semiology: further insights into vascular features by screening a large spectrum of nontumoral skin lesions. Br. J. Dermatol. 2004;150:226-31. PMID: 14996092.
- ↑ 10.0 10.1 10.2 Lallas et al.: Dermoscopy of early stage mycosis fungoides. J Eur Acad Dermatol Venereol 2013;27:617-21. PMID: 22404051. DOI.
- ↑ Zalaudek & Argenziano: Dermoscopy subpatterns of inflammatory skin disorders. Arch Dermatol 2006;142:808. PMID: 16785400. DOI.
- ↑ Vazquez-Lopez et al.: Dermoscopy for discriminating between lichenoid sarcoidosis and lichen planus. Arch Dermatol 2011;147:1130. PMID: 21931067. DOI.
- ↑ Chuh: Collarette scaling in pityriasis rosea demonstrated by digital epiluminescence dermatoscopy. Australas. J. Dermatol. 2001;42:288-90. PMID: 11903165.
- ↑ Chuh: The use of digital epiluminescence dermatoscopy to identify peripheral scaling in pityriasis rosea. Comput Med Imaging Graph 2002;26:129-34. PMID: 11818191.
- ↑ 15.0 15.1 Abdel-Azim et al.: Differentiation of pityriasis rubra pilaris from plaque psoriasis by dermoscopy. Arch. Dermatol. Res. 2017;309:311-314. PMID: 28280914. DOI.
- ↑ López-Gómez et al.: Dermoscopy of circumscribed juvenile pityriasis rubra pilaris. J. Am. Acad. Dermatol. 2015;72:S58-9. PMID: 25500045. DOI.
- ↑ Lallas et al.: Photoletter to the editor: Dermoscopy for discriminating between pityriasis rubra pilaris and psoriasis. J Dermatol Case Rep 2013;7:20-2. PMID: 23580911. DOI.
- ↑ Delfino et al.: Dermoscopy for the diagnosis of porokeratosis. J Eur Acad Dermatol Venereol 2004;18:194-5. PMID: 15009303.
- ↑ Zaballos et al.: Dermoscopy of disseminated superficial actinic porokeratosis. Arch Dermatol 2004;140:1410. PMID: 15545557. DOI.
- ↑ Pizzichetta et al.: Clinical and dermoscopic features of porokeratosis of Mibelli. Arch Dermatol 2009;145:91-2. PMID: 19153357. DOI.
- ↑ Uhara et al.: Open pores with plugs in porokeratosis clearly visualized with the dermoscopic furrow ink test: report of 3 cases. Arch Dermatol 2011;147:866-8. PMID: 21768494. DOI.
- ↑ Zaballos et al.: Dermoscopy of disseminated superficial actinic porokeratosis. Arch Dermatol 2004;140:1410. PMID: 15545557. DOI.
- ↑ Oiso & Kawada: Dermoscopic features in disseminated superficial actinic porokeratosis. Eur J Dermatol 2011;21:439-40. PMID: 21680280. DOI.
- ↑ Panasiti et al.: Disseminated superficial actinic porokeratosis diagnosed by dermoscopy. Int. J. Dermatol. 2008;47:308-10. PMID: 18289344. DOI.
- ↑ 25.0 25.1 Pellicano et al.: Dermoscopy of cutaneous sarcoidosis. Dermatology (Basel) 2010;221:51-4. PMID: 20375489. DOI.
- ↑ Bakos et al.: Dermatoscopy of early-onset necrobiosis lipoidica. J. Am. Acad. Dermatol. 2012;66:e143-4. PMID: 22421129. DOI.
- ↑ 27.0 27.1 Balestri et al.: Dermoscopic subpatterns of granulomatous skin diseases. J. Am. Acad. Dermatol. 2013;69:e217-8. PMID: 24124838. DOI.
- ↑ 28.0 28.1 28.2 Pellicano et al.: Dermoscopy of necrobiosis lipoidica and granuloma annulare. Dermatology (Basel) 2013;226:319-23. PMID: 23797090. DOI.
- ↑ 29.0 29.1 Brasiello et al.: Lupus vulgaris: a new look at an old symptom--the lupoma observed with dermoscopy. Dermatology (Basel) 2009;218:172-4. PMID: 19060460. DOI.
- ↑ Llambrich et al.: Dermoscopy of cutaneous leishmaniasis. Br. J. Dermatol. 2009;160:756-61. PMID: 19120331. DOI.
- ↑ 31.0 31.1 Bakos et al.: Dermatoscopy of early-onset necrobiosis lipoidica. J. Am. Acad. Dermatol. 2012;66:e143-4. PMID: 22421129. DOI.
- ↑ Lallas et al.: Dermoscopy of discoid lupus erythematosus. Br. J. Dermatol. 2013;168:284-8. PMID: 22985425. DOI.
- ↑ Segal et al.: Dermoscopy as a diagnostic tool in demodicidosis. Int. J. Dermatol. 2010;49:1018-23. PMID: 20931672.
- ↑ Larre Borges et al.: Clinical, dermoscopic and histopathologic features of genital and extragenital lichen sclerosus. J Eur Acad Dermatol Venereol 2013;27:1433-9. PMID: 22646723. DOI.
- ↑ Garrido-Ríos et al.: Dermoscopy of extragenital lichen sclerosus. Arch Dermatol 2009;145:1468. PMID: 20026867. DOI.
- ↑ Shim et al.: Diagnostic usefulness of dermatoscopy in differentiating lichen sclerous et atrophicus from morphea. J. Am. Acad. Dermatol. 2012;66:690-1. PMID: 22421117. DOI.
- ↑ Vázquez-López et al.: Dermoscopy for the screening of common urticaria and urticaria vasculitis. Arch Dermatol 2008;144:568. PMID: 18427065. DOI.
- ↑ Vázquez-López et al.: Surface microscopy for discriminating between common urticaria and urticarial vasculitis. Rheumatology (Oxford) 2003;42:1079-82. PMID: 12730524. DOI.
- ↑ Zaballos et al.: Dermoscopy of pigmented purpuric dermatoses (lichen aureus): a useful tool for clinical diagnosis. Arch Dermatol 2004;140:1290-1. PMID: 15492206. DOI.
- ↑ Zalaudek et al.: [Atypical clinical presentation of pigmented purpuric dermatosis]. J Dtsch Dermatol Ges 2006;4:138-40. PMID: 16503941. DOI.
- ↑ Vázquez-López et al.: The handheld dermoscope improves the recognition of giant pseudocomedones in Darier's disease. J. Am. Acad. Dermatol. 2004;50:454-5. PMID: 14988691. DOI.
- ↑ Akay et al.: Dermatoscopic findings of cutaneous mastocytosis. Dermatology (Basel) 2009;218:226-30. PMID: 19060465. DOI.
- ↑ 43.0 43.1 Vano-Galvan et al.: Dermoscopic features of skin lesions in patients with mastocytosis. Arch Dermatol 2011;147:932-40. PMID: 21844452. DOI.
- ↑ Ohnishi et al.: Angioma serpiginosum: a report of 2 cases identified using epiluminescence microscopy. Arch Dermatol 1999;135:1366-8. PMID: 10566835.
- ↑ Lallas et al.: Photoletter to the editor: Dermoscopy of granuloma faciale. J Dermatol Case Rep 2012;6:59-60. PMID: 22826723. DOI.