Surface microscopy for discriminating between common urticaria and urticarial vasculitis
F. Vázquez-López,
C. Maldonado-Seral,
T. Soler-Sánchez1,
N. Perez-Oliva1 and
A. A. Marghoob2
Department of Dermatology and
1 Department of Pathology, Central University Hospital, University of Oviedo, Oviedo, Spain and
2 Department of Dermatology, Memorial Sloan-Kettering Cancer Center, New York, USA
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Abstract
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Background. Urticarial vasculitis is a clinicopathological entity that overlaps with common urticaria, and biopsy is required for differentiation between them.
Objective. To determine, for the first time, if skin surface microscopy can aid in the clinical differentiation between common urticaria and urticarial vasculitis in daily practice.
Patients and methods. Lesions in 20 consecutive patients with a clinical diagnosis of urticaria were studied by biopsy and skin surface microscopy (10x dermoscope) after covering the lesions with olive oil. Lesions were photographed with Dermaphot equipment. A biopsy was taken from all patients. Statistical analysis included Fisher's exact test and Cohen
statistics (intra-observer reproducibility).
Results. Two dermoscopic patterns were observed: (i) a red-lined vascular pattern (17/20 patients); and (ii) a purpuric globular pattern (3/20 patients). Leucocytoclastic vasculitis was demonstrated histologically in all lesions presenting purpuric globules (3/3) but in none of the lesions presenting a dermoscopic red-lined pattern (P < 0.0008). The intra-observer reproducibility for scoring the red lines and purpuric globules was excellent (
=0.8).
Conclusion. The results of this pilot study suggest that skin surface microscopy, using a 10x dermoscope, detects purpuric globules in urticarial lesions, and that purpuric globules indicate underlying leucocytoclastic vasculitis.
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Introduction
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Urticarial vasculitis (UV) is a clinicopathological entity that overlaps with common urticaria (CU), and biopsy is required to differentiate them. This discrimination is important because UV may be a cutaneous manifestation of an underlying connective tissue disease process [1]. We report, for the first time, the apparent value of surface microscopy as a non-invasive, cost-efficient method for improving the clinical differentiation between CU and UV in daily practice by revealing microscopic components of clinically inapparent purpura in the erythematous lesions of urticaria vasculitis.
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Patients, methods and definitions
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Twenty consecutive patients with a clinical diagnosis of urticaria were studied (11 females and nine males, aged 1972 yr, mean age 45.1 yr). Lesions were erythematous papules or wheals. For each patient, we biopsied an urticarial lesion on the trunk. According to previous studies [2, 3], histological criteria for diagnosing UV include: (i) deposition of fibrin within the vessels wall; (ii) perivascular and interstitial infiltrates of neutrophils; (iii) signs of karyorrhexis (nuclear dust); and (iv) extravasation of erythrocytes. These criteria were used in histological evaluation by two observers without knowledge of the dermoscopic results.
We also investigated each patient's lesions by skin surface microscopy. Skin surface microscopy was performed with a 10x dermoscope (Delta 10; Heine Optotechnik, Herrshing, Germany) and lesions were photographed with Dermaphot photographic equipment (Heine Optotechnik). Lesions were evaluated on the trunk. Dermoscopic visualization involves application of oil to the surface of the lesion, rendering the stratum corneum translucent. The dermoscope is then placed over the lesion, which is illuminated by incident light. At 10x magnification, the dermoscope reveals epidermal and upper dermal structures, including superficial vessels and extravascular pigment. The usual precautions must be taken in order to prevent nosocomial infections in the presence of erosions or microhaemorrhages on the skin lesions.
To characterize the findings in these patients, we used our own dermoscopic classification, based on certain vascular and purpuric structures [4, 5]. The red vascular structures are as follows: (i) red dots (round or punctate, representing normal papillary capillaries); (ii) red globules (larger round structures, representing ectatic or elongated papillary vessels); (iii) red lines (linear vessels of the horizontal subpapillary plexus); (iv) oblique red lines (oblique linear vessels along the edges of raised lesions); and (v) convoluted, glomerulus-like vascular structures. The purpuric structures are as follows: (i) homogeneous purpura, caused by non-inflammatory dermal haemorrhage; (ii) small purpuric globules derived from perivascular haemorrhage associated with inflammatory purpura; and (iii) subcorneal purpura. The colour of the background field may surround these defined vascular structures, or, when it is prominent, obscure the vascular structures. In the present study, each of the features was scored as present or absent, without grading.
Statistical analysis was performed with Fisher's exact test. The most significant features were used for evaluating the differentiation between CU and UV. The sensitivity for the diagnosis of UV was equal to the number of patients scored positive for UV divided by the total number of cases of UV (expressed as a percentage). The specificity for the diagnosis of UV (using the CU model) was equal to the number of patients scored negative for CU divided by the total number of cases of CU (expressed as a percentage). The intra-observer reproducibility for scoring the presence or absence of the most significant criteria was assessed by means of a blind testretest set, and using Cohen's
statistics as a measure of agreement corrected for chance [6].
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Results
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In 17 out of 20 patients, a red-lined vascular pattern was observed in the urticariform lesions (papules or wheals). In some lesions, linear vessels surrounded negative areas devoid of vascular findings (Figs 1 and 2
). In three out of 20 patients a purpuric pattern (showing purpuric globules or dots) was demonstrated in the lesions (Fig. 3
). Biopsy of these three patients, which showed a red-lined or negative pattern (areas devoid of vascular findings) did not disclose vasculitis in any of them (0/17). Although some of these patients showed perivascular neutrophilic infiltrates, none fulfilled criteria used for vasculitis and they did not show nuclear dust, fibrin deposition within the vessel wall or erythrocyte extravasation. On the other hand, all patients (3/3) showing a dermoscopic purpuric pattern (purpuric globules) presented underlying leucocytoclastic vasculitis (showing fibrin deposits, nuclear dust and dermal hemorrhages) (Fisher's exact test, P < 0.0008). The intra-observer reproducibility for scoring the purpuric globules and red lines was excellent (
=0.828). In this model (CU vs UV), the feature of purpuric globules had a sensitivity of 100% (3/3) for the diagnosis of UV and a specificity of 100% (17/17) for the diagnosis of CU.

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FIG. 1. Common urticaria. Dermoscopic view showing a red-lined pattern surrounding a negative area with prominent dermal oedema.
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FIG. 2. Common urticaria. Dermoscopic view of a wheal, showing ectatic reticular red capillaries (red-lined pattern).
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FIG. 3. Urticarial vasculitis. Dermoscopic view of a papule showing purpuric dots and globules (purpuric pattern), related to vascular damage and erythrocyte extravasation. This finding was observed in 3/3 patients with urticarial vasculitis.
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Comments
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Skin surface microscopy is a non-invasive technique that allows in vivo microscopic examination of the skin. The findings must be interpreted in conjunction with clinical examination to facilitate clinical diagnosis. Briefly, surface microscopy is a two-step process. First, the skin lesion is covered with olive oil, which eliminates surface reflection due to the mismatch in refractive index between air and skin. This renders the stratum corneum transparent, enabling in vivo visualization of subsurface structures. The second step requires the use of special instruments equipped with a standard magnifying objective and a transilluminating light source. Degrees of magnification vary from 6x to 400x. To achieve high magnification, large, expensive binocular microscopes are required (epiluminescence microscopy). Inexpensive handheld instruments (dermoscopes) have also been developed which allow a fixed magnification of 10x, and this is now the favoured means of magnification in most studies of pigmented skin lesions. Video cameras and electronic imaging systems have also been introduced. These devices permit more detailed inspection of the skin lesions, offering a new in vivo view of the epidermis, dermo-epidermal junction and superficial dermis, revealing structures not visible to the naked eye.
Skin surface microscopy of non-tumoural skin lesions has been mainly applied to the study of the nailfold [7]. The screening of patients with Raynaud's phenomenon and the diagnosis of systemic sclerosis have been its most common applications [810]. Most studies have been made with sophisticated instruments (such as the stereomicroscope and videomicroscope), and there are few reports using the simpler dermoscope [4, 5, 11, 12]. Our results show that surface microscopy may have a useful new application in addition to its use in examining the nailfold in daily practice: the clinical discrimination between CU and UV by revealing hidden components of purpura in erythematous UV but not in CU. Moreover, the use of the dermoscope renders surface microscopy more available in daily practice. Ophthalmoscopy has also been proposed for nailfold capillaroscopy, but the dermoscope costs less than the standard ophthalmoscope and seems to be superior [12], although a direct comparison has not been performed. The value of skin surface microscopy for the diagnosis of melanoma and other pigmented skin tumours has been confirmed by evidence-based meta-analyses [13].
As regards the dermoscopic patterns reported herein, the red-lined pattern corresponds histologically with transient ectatic/elongated, filled horizontal subpapillary vessels, which are obscured if prominent oedema is present in urticariform lesions (negative areas). There are two main purpuric dermoscopic patterns [4]: (i) large, homogeneous purpuric areas devoid of definite vascular features, which are related to non-inflammatory purpuric lesions, such as senile purpura and corticoid-induced purpura, with homogeneous and prominent dermal haemorrhages; and (ii) purpuric dots/globules, which are associated with a lesser degree of superficial, extravasated red blood cells with or without vascular necrosis, and which are correlated with different forms of inflammatory purpuric lesions (vasculitis, pigmented purpuric dermatoses) [4]. In the present study, the presence of purpuric globules on urticarial lesions was correlated with subclinical vasculitis. We applied a strict definition of vasculitis, including four criteria (fibrin deposits, nuclear dust, neutrophilic infiltrates and erythrocyte extravasation), although early lesions of leucocytoclastic vasculitis still did not show fibrin deposits within the vessels [3]. As regards the histological differentiation between CU and UV lesions, nuclear dust and dermal haemorrhages have been considered the most specific differential criteria, being present only in UV and not in CU [3]. Our dermoscopic results agree with this in the sense that dermal haemorrhages (purpuric globules) were observed only in lesions with well-developed vasculitis, and not in CU lesions.
To conclude, updating and improving the classic glass-slide diascopy method [14], the capillaroscopic (dermoscopic) recognition of a purpuric globular pattern in urticariform lesions may help as a first-line clinical screening tool for discriminating between UV and CU in daily practice (P < 0.0008).
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Notes
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Correspondence to: F. Vázquez López, C/Ezcurdia 192, 3M 33203 Gijón, Spain. E-mail: fvlopez{at}telecable.es 
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References
|
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- Wisnieski JJ. Urticarial vasculitis. Curr Opin Rheumatol 2000;12:2431.[CrossRef][ISI][Medline]
- Peteiro C, Toribio J. Incidence of leukocytoclastic vasculitis in chronic idiopathic urticaria. Study of 100 cases. Am J Dermatopathol 1989;11:52833.[ISI][Medline]
- Ackerman AB. Histologic diagnosis of inflammatory skin diseases. Baltimore: Williams and Wilkins, 1997.
- Vázquez-López F, Alvarez C, Hidalgo Y, Pérez Oliva N. Utility of the handheld dermoscope as an aid for the clinical examination of inflammatory dermatoses. Actas Dermosifiliogr 2001;92(Suppl. 3):128.
- Vázquez-López F, Manjón Haces JA, Vázquez-López AC, Pérez Oliva N. The handheld dermatoscope improves the clinical evaluation of port-wine stains. J Am Acad Dermatol 2003; 48:in press.
- Stanganelli I, Burroni M, Rafanelli S, Bucchi L. Intraobserver agreement in interpretation of digital epiluminescence microscopy. J Am Acad Dermatol 1995;33:5849.[ISI][Medline]
- Carpentier PH. New techniques for clinical assessment of the peripheral microcirculation. Drugs 1999;58(Special Issue 1)1722.
- Lonzetti LS, Joyal F, Raynauld JP et al. Updating the American College of Rheumatology preliminary classification criteria for systemic sclerosis: addition of severe nailfold capillaroscopy abnormalities markedly increases the sensitivity for limited scleroderma. Arthritis Rheum 2001;44:7358.[CrossRef][ISI][Medline]
- Bukhari M, Hollis S, Moore T, Jayson MIV, Herrick AL. Quantitation of microcirculatory abnormalities in patients with primary Raynaud's phenomenon and systemic sclerosis by video capillaroscopy. Rheumatology 2000;39:50612.[Abstract/Free Full Text]
- Tektonidou M, Kaskani E, Skopouli FN, Moutsopoulos HM. Microvascular abnormalities in Sjögren's syndrome: nailfold capillaroscopy. Rheumatology 1999;38:82630.[Abstract/Free Full Text]
- Vázquez-López F, Alvarez-Cuesta CC, Hidalgo García Y, Pérez Oliva N. The handheld dermatoscope improves the recognition of Wickham striae and capillaries in lichen planus lesions. Arch Dermatol 2001;137:1376.[Free Full Text]
- Bauersachs RM, Löbner F. The poor man's capillary microscope. A novel technique for the assessment of capillary morphology. Ann Rheum Dis 1997;56:4357.[Abstract/Free Full Text]
- Bafounta ML, Beauchet A, Aegerter P, Saiag P. Is dermocopy (epiluminescence microscopy) useful for the diagnosis of melanoma? Arch Dermatol 2001;137:134350.[Abstract/Free Full Text]
- MV Dahl. Clinical pearl: diascopy helps diagnose urticarial vasculitis. J Am Acad Dermatol 1994;30:4812.[ISI][Medline]
Submitted 24 September 2002;
Accepted 5 February 2003