Demodex Induced Blepharitis Diagnosed by In Vivo Confocal Microscopy
Published Date: July 31, 2017.
Demodex Induced Blepharitis Diagnosed by In Vivo Confocal Microscopy
Cinotti E1*, Fiorani D1, Labeille B2, Cambazard F2, Rubegni P1 and Perrot JL2
1Department of Medical, Surgical and Neurological Science, Dermatology Section, University of Siena, S. Maria alle Scotte Hospital, Siena, Italy
2Department of Dermatology, University Hospital of St-Etienne, St-Etienne, France
*Corresponding author: Cinotti E, Department of Medical, Surgical and Neurological Science, Dermatology Section, University of Siena, S. Maria alle Scotte Hospital, Siena, Italy, E-mail: email@example.com.
Citation: Cinotti E, Fiorani D, Labeille B, Cambazard F, Rubegni P, et al. (2017) Demodex Induced Blepharitis Diagnosed by In Vivo Confocal Microscopy. J Derma Pigm Res 1(1): 105.
Demodex folliculorum can colonize eyelash infundibulum and induce blepharitis. The clinical diagnosis of Demodex induced blepharitis is often challenging and a microscopic identification of Demodex in epilated lashes or in eyelids scrapings is necessary. The aim of our study was to verify if in vivo Reflectance Confocal Microscopy (RCM), a noninvasive emerging imaging technique, can identify Demodex folliculorum in eyelash infundibulum allowing to avoid other invasive procedures.
Keywords: Reflectance confocal microscopy; In vivo; Non-invasive imaging; Demodex infestation; Blepharitis
Demodex is the most common parasite in humans and is implicated in several skin diseases such as rosacea, papulopustular eruptions, and perioral dermatitis. Demodex mites are also responsible for several ocular surface diseases such as blepharitis, ocular rosacea, and dry eye syndrome. Only Demodex folliculorum and Demodex brevis can be detected on the human body. They can be found in the eyelids, cilia, meibomian glands, face and external ear tract. Demodex folliculorum, commonly found in the small hair follicle, measures about 0.35–0.4 mm and causes chronic anterior blepharitis; Demodex brevis, responsible of posterior blepharitis, is 0.15–0.2 mm in diameter and lives deep in the sebaceous glands. In the eye, Demodex folliculorum is found in the lash follicle, whereas Demodex brevis burrows deep into the lash’s sebaceous gland and the meibomian glands [1,2]. Both parasites can colonize eyelash infundibulum and induce blepharitis. Infection of Demodex often occurs in the course of chronic blepharitis; in patients having blepharitis, the prevalence of Demodex infestation rises with an increase of the age, being observed in 84% of the population at the age of 60 years and is 100% in people > 70 years . The clinical diagnosis of Demodex induced blepharitis is often challenging. So far all diagnostic approaches, such as microscopic identification of Demodex in epilated lashes or in eyelids scrapings, are (semi)-invasive and may cause discomfort to the patients. Reflectance confocal microscopy (RCM) represents a reliable tool for a noninvasive-in vivo diagnosis of Demodex induced blepharitis. Two in vivo ophthalmologic reflectance confocal microscopes are available to explore the eye surface: a 4-slit scanning confocal microscope (Confoscan; Nidek Technologies) and a laser-scanning confocal microscope (Heidelberg Retina Tomograph; Heidelberg Engineering GmbH). However, both microscopes are not very handy; they are used mostly to examine the cornea, they are rarely utilized for the conjunctiva or eyelid margin. Demodex have already been detected with the help of ophthalmologic confocal microscopy, but we have demonstrated that also the skin dedicated RCM can identify Demodex folliculorum in the eyelash infundibulum. The handheld skin dedicated device has a greater handling compared to the ophthalmologic one with a consequent faster examination. We report a case of blepharitis due to Demodex folliculorum in a healthy 67-year-old man presenting with a conjunctival hyperemia and eyelid erythema for several months that has been evaluated by handheld skin dedicated RCM.
A male patient, aged 67, suffered from blepharitis with conjunctival hyperemia, eyelid erythema, and desquamation for several months. In order to identify a possible Demodex induced blepharitis, he was investigated for the use of handheld in vivo skin dedicated reflectance confocal microscopy, a non-invasive emerging technique that has a nearly histological resolution (Figure 1a). Demodex mites have been implicated not only in blepharitis but also in several cutaneous diseases such as papulopustular rosacea, pityriasis folliculorum, rosacea-like demodicosis, perioral dermatitis, and RCM had already been proved effective for the search of Demodex in the skin .
Skin dedicated RCM (VivaScope 3000®, Caliber, distributed in Europe by MAVIG) was performed to search Demodex mites in the whole ciliary margin. This tool is equipped with an 830 nm diode laser which is completely safe for the eyes (class 1B classification; Center for Devices and Radiological Health). Every image is in the gray scale and corresponds to a horizontal 920 × 920 μm section up to 250 μm in depth from the epithelial surface to the stroma with a high optical resolution (horizontal and vertical axis: 1.25 μm and 5 μm, respectively). Before the ocular examination, a topical anesthesia was performed with one drop of oxybuprocaine hydrochloride 1.6 mg/0.4 ml and one drop of tetracaine hydrochloride 1% in the inferior conjunctival fornix of the eye.
A transparent ophthalmic gel of Carbomer 974P (Gel larme, Théa, Clermont-Ferrand, France) was placed on the ocular region to be examined, and a disposable sterile transparent film (Visulin®, Paul Hartmann AG, Germany) was applied on the RCM tip. The examination was performed with the patient in a supine position.
Skin dedicated RCM easily identified Demodex folliculorum in the infundibulum of the majority of the eyelashes (Figure 1b) and in the space adjacent to the eyelash shafts (Figure 1c) as hypo-reflective elongated bodies with hyperreflective heads. Sixty images (30 for the left eye and 30 for the right one) of consecutive infundibula were acquired. Mites ranged from 0 to 6 per infundibulum (with a mean of 4.2 and a standard deviation of 1.6). Moreover, RCM showed dilated ducts of the meibomian glands filled with debris (Figure 1d, 1e). Demodex brevis was never identified. The examination took 10 minutes and the patient did not complain about any discomfort during the examination.
A patient without blepharitis, presenting with an eyelid tumor, was also investigated to search Demodex mites. This patient presented neither Demodex in the eyelid margin nor meibomian glands alterations.
Figure 1: (a) Clinical aspect of the patient with Demodex induced blepharitis. (b) Reflectance in vivo confocal microscopy (RCM) aspect of an eyelash infundibulum crammed with parallel-elongated bodies corresponding to Demodex folliculorum. (c) RCM showed Demodex folliculorum in the space adjacent to the eyelash shaft (arrows). (d,e) RCM showed dilated ducts of the meibomian glands filled with debris in transverse (circles) and sagittal (arrows) views.
Although cylindrical dandruff has been regarded as pathognomonic of Demodex infestation , the diagnosis of Demodex infestation is often challenging. The clinical presentation is often can specific presenting with red, itchy, watery eyes and eyelid desquamation, thus mimicking other conditions such as seborrheic dermatitis, irritative dermatitis, contact allergy and bacterial infections. The final diagnosis is based on the microscopic identification of Demodex mites and relies on the microscopic counting of mites in randomly epilated eyelashes mounted with a cover slip after addition of a drop of oil.
Recently, it has been observed that the addition of fluorescein solution further increases the possibility of detecting and counting mites embedded in cylindrical dandruff or epilated eyelashes under light microscopy .
RCM represents a new non-invasive and reliable tool for the identification and quantification of the mite.
D. folliculorum is easy to be recognized by RCM in cutaneous hair follicles. The ophthalmologic confocal microscope Heidelberg Retina Tomograph (Heidelberg Engineering GmbH, Heidelberg, Germany) could also identify Demodex folliculorum near an eyelash shaft of one patient with chronic blepharitis [6,7]. Our case demonstrated that also the skin-dedicated handled camera VivaScope 3000 can identify Demodex of the eyelid margin. This device is easier to handle compared to the ophthalmologic confocal microscope and enables an easy exploration of the whole ciliary margin, identifying mites in and outside of the hair infundibulum. In addition, RCM dedicated to the skin permits to search Demodex mite both in facial skin and eyelid mucosa, localizations that are often associated, like in rosacea. In facial rosacea Demodex appears as an elongated or roundish-shaped structure in hair follicles [1,8], whereas in the eyelid margin, due to the particular orientation of the eyelashes with respect to the surface of the camera, it presents with an elongated body in the eyelash infundibulum or in the space adjacent to the eyelash shaft. In the skin, the presence of ≥ 4 mites in at least one follicle is rated positive for pathological mite infestation [1–9]. We suggest the same criterion to be used for Demodex induced blepharitis, as our patient had the majority (about 75%) of his eyelid infundibulum crammed with mites, often ≥ 4.
Demodex brevis can also colonize eyelid, but we were not able to visualize it by RCM, probably because it merges with the content of the sebaceous and meibomian glands. However, RCM can explore meibomian glands to provide indirect signs of its presence. In rosacea, Demodex blocks gland orifices mechanically  and therefore it frequently triggers chalazion . The obstructed glands filled with debris have already been identified by RCM in rosacea and can be considered an additional sign of Demodex-induced blepharitis in contrast with bacterial infection . Randon et al.  have detected D. brevis with the help of ophthalmologic RCM: the parasite was seen at the very bottom of the follicle or inside the meibomian glands meatus. Usually one or two mites were present causing gland obstruction and reactional epithelial proliferation. In our study, we also evaluated a patient without blepharitis, in order to verify the absence of Demodex mites. In this negative control, no elongated or roundish structures corresponding to mites were found inside the follicular openings.
RCM has been demonstrated to be a reliable and efficient tool offering a parasite count that is not inferior to conventional techniques such as skin scraping. Randon et al.  have evaluated 18 patients suffering from anterior blepharitis with RCM and with classical depilation technique in order to compare these diagnostic procedures: RCM not only detected mites in all patients as depilation technique but also allowed a detection of Demodex brevis and Demodex larvae inside the lash follicle. Furthermore, patients who were investigated with RCM showed a superior compliance compared to those evaluated with the conventional technique and this was due to the absence of invasiveness and pain and the quick and faster examination.
Reflectance confocal microscopy is a modern imaging tool, useful not only for the diagnosis of skin tumors and inflammatory conditions but also for the infestation. Advantages of RCM compared to the conventional diagnostic procedures are the rapidity of evaluation and the possibility to perform seriated examination to ensure mite eradication, especially after treatment [5–11]. Moreover, RCM allows the identification of mites in their real environment whereas with the other techniques the mites could be partially taken off with a potential incorrect counting . Besides a direct identification of Demodex, RCM can also show meibomian glands involvement that is an additional clue for the diagnosis . Moreover, it can examine both the eyelid and the skin being able to observe the infestation of both the eyelashes and the skin that is common in demodicosis and rosacea. Handheld skin dedicated device, differently from the ophthalmologic one, allows imaging of a larger field of view (920 × 920 µm versus 400 × 400 µm) and can be particularly handy representing a useful tool in clinical practice for the examination of the eyelid margin.
Conflict of Interest
The authors declared that there is no conflict of interest.
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Copyright: © 2017 Cinotti E, et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.