Case Report

Demodex Folliculorum can Cause Pyogenic Granuloma of Conjunctiva

by Don S Minckler1*, Richard R Weiss2, Maria Del Valle Estopina1,3, Cassiana E Bittencourt4

1Emeritus Professor of Ophthalmology and Glaucoma Director, Clinical Professor Laboratory Medicine (Ophthalmic Pathology), University of California Irvine Medical School, USA

2Private Practice Ophthalmic Plastic Surgery, Newport, CA, USA

3Assistant Professor Departments of Pathology and Ophthalmology, Director of Ophthalmic Pathology Division, University of California Irvine, USA

4Assistant Professor, Department of Laboratory Medicine, Director of Microbiology, University of California Irvine, USA

*Corresponding author: Don S Minckler, Emeritus Professor of Ophthalmology and Glaucoma Director, Clinical Professor Laboratory Medicine (Ophthalmic Pathology), University of California Irvine Medical School, USA

Received Date: 11 December 2023

Accepted Date: 17 December 2023

Published Date: 21 December 2023

Citation: Minckler DS, Weiss RR, Estopinal MDV, Bittencourt CE (2023) Demodex Folliculorum can Cause Pyogenic Granuloma of Conjunctiva. Arch Surg Clin Case Rep 6: 212.


An elderly Caucasian female with a history of oral lichen planus and functional nasolacrimal obstruction underwent bilateral Dacryocystorhinostomy (DCR). Eight months later tearing symptoms recurred, right greater than left, and a right lower medial eyelid inflammatory process was clinically correctly diagnosed as pyogenic granuloma. Excision and drainage without pathology was performed but the inflammation continued despite topical therapy with steroids and antibiotics. Clinical suspicion of conjunctival lichen planus prompted serial topical mitomycin-C applications effecting slight improvement over six-months. Persistence of the lesion led to a biopsy initially interpreted as pyogenic granuloma and subsequent step-sections of the specimen demonstrated a cyst containing probable parasite debris. A second deeper biopsy three months later revealed only granulation tissue. Thereafter the problematic area gradually healed. Controversy as to what parasite was responsible prompted a Center for Disease Control consult resulting in an unexpected diagnosis of Demodex folliculorum. Methods: We reviewed all clinical and pathology records related to this case. She had not traveled out of her home area or visited any agricultural fair or farm and did not remember any insect bites. Results: Parasitic debris was initially thought consistent with the external cuticle of a fly larva such as Oestrus Ovis [Sheep bot fly]. Eventual consultation with the Center for Disease Control resulted in a diagnosis of inflammation residual to Demodex folliculorum migration into conjunctival stroma. Conclusion: Persisting conjunctival inflammation can be due to Demodex folliculorum stromal invasion to locations far from eyelid skin, the common site of mite infestation.

Case Report

An otherwise healthy 78-year- old Caucasian female with a history of oral lichen planus presented to RRW on 8/18/08 (Figure 1) with a one-year history of continual bilateral tearing, greater on the right. There was no pain or foreign body sensation. She was sensitive to lacrimal probing, which demonstrated anatomically patent lacrimal drainage systems but with copious reflux from the non-cannulated punctum bilaterally justifying a diagnosis of functional nasolacrimal system obstruction. Bilateral Dacryocystorhinostomies (DCR) were performed on 8/19/09. The surgical procedures were initially successful through five months post-operatively during which she was tearing free. However, by eight months post DCR the tearing had recurred bilaterally. In addition, a conjunctival inflammatory process was obvious on eversion of her right lower eyelid (Figure 2). Non-response to topical lubrication steroids and antibiotics prompted an initial incision and drainage for presumed pyogenic granuloma or chalazion without pathology. The inflammatory process slowly recurred including a purulent appearing microcyst (Figure 3) leading to a conjunctival biopsy sent to Eye Pathology at UCI 11/18/2010, one-year following the DCR. Clinical photos before the first excision revealed a purulent micro-cyst, correlating with the histology demonstrating a pyogenic granuloma (Figure 2-4). Pathologic study revealed incompletely excised micro-nodules of acutely and chronically inflamed granulation tissue partially covered by conjunctiva with focal pseudoepitheliomatous hyperplasia, necrosis and crush artifact. Step-sections of the deeper portions of the first specimen revealed non-polarizing membranous debris, suggestive of chitin of insect or parasite origin, within a well-defined fibrous envelope (Figure 5). In-spite of treatment by multiple other ophthalmologists, topical steroids, antibiotics, and twelve serial 0.02% mitomycin-C topical applications over six months recommended by consultants who suspected conjunctival lichen planus, the lesion persisted leading to a second deeper excisional biopsy three months later revealing only granulation tissue. After this second biopsy the area eventually healed with no recurrence.


Figure 1: Initial clinical appearance of right lower eyelid inflammation 8/18/2008.