Original Research

Ocular Manifestations of Patients With Cutaneous Rosacea With and Without Demodex Infection

Author and Disclosure Information

Rosacea is a chronic progressive disease that causes inflammation on the skin and the ocular surface. This study aimed to evaluate the effects of Demodex mites on clinical findings associated with rosacea. Sixty patients who were newly diagnosed with rosacea in the dermatology outpatient clinic underwent superficial skin biopsy to determine the density of Demodex species. The patients were evaluated as Demodex positive (n=30) or Demodex negative (n=30) based on the species density. The 60 patients were examined in the ophthalmology outpatient clinic; a total of 120 eyes underwent tear breakup time (TBUT) and Schirmer tests and were examined for meibomitis and blepharitis findings. The demographic characteristics and ocular findings of both groups were recorded and statistically compared. We found that Demodex mite–related inflammation in rosacea does not significantly affect clinical ocular surface findings and that Demodex positivity is significantly associated with papulopustular rosacea (PPR)(P=.003).

Practice Points

  • Rosacea is a common chronic inflammatory skin disease of the central facial skin and is of unknown origin. Patients with ocular rosacea may report dryness, itching, and photophobia.
  • Demodex infestation may increase cutaneous or ocular inflammation in rosacea.



Acne rosacea is a chronic inflammatory disease that may affect the facial skin, eyes, and eyelids.1 It is characterized by transient or persistent flushing, facial erythema, and telangiectases, generally located on the central portion of the face, and may progress to papules and pustules.2,3 At the late stage of the disease, dermal edema or fibroplasia and sebaceous gland hypertrophy may cause phymatous alterations in the skin. In 2004, the National Rosacea Society Expert Committee developed a classification system for rosacea to standardize subtypes and variants that has since been widely accepted and continues to aid in research and epidemiologic studies.4 The committee defined 4 subtypes based on clinical characteristics: erythematotelangiectatic (ETR), papulopustular (PPR), phymatous, and ocular rosacea.2,3

Ocular rosacea may accompany mild, moderate, and severe dermatologic disease or may occur in the absence of diagnostic skin disease.5 Ocular signs include eyelid margin telangiectasia, spade-shaped infiltrates in the cornea, scleritis, and sclerokeratitis. Common symptoms include burning, stinging, light sensitivity, and foreign-body sensation. Ocular signs commonly seen in rosacea are meibomian gland dysfunction characterized by inspissation and inflammation of the meibomian glands (chalazia), conjunctivitis, honey crust and cylindrical collarette accumulation at the base of the eyelashes, irregularity of the eyelid margin architecture, and evaporative tear dysfunction.5,6

The physiopathology of rosacea is still unknown. Potential factors include genetic predisposition, abnormal inflammation, vascular dysfunction, and involvement of several microbial agents, such as commensal Demodex mites. The number of Demodex mites on normal skin flora is less than 5/cm2; however, the increased vascular dilation and capillary permeability associated with rosacea that result from sunlight and heat exposure increase the density of Demodex folliculorum.7 Elevated Demodex mite density has been observed in the lumens of the sebaceous follicles in patients with rosacea. However, because the severity of the clinical manifestations of the disease is not directly associated with the density of D folliculorum, it generally is accepted that D folliculorum is not a pathogenetic but rather an exacerbating factor.8 It has been reported that this species of mite is mostly found on the face and around the eyelashes and scalp of patients and that it can cause ocular surface inflammation.8

Most studies have researched ocular manifestations of rosacea but not ocular involvement in rosacea patients with and without Demodex mite infestation. In our study, we sought to compare the ocular surface, meibomian gland characteristics, and tear film abnormalities among patients with cutaneous rosacea with and without Demodex infestation.

Materials and Methods

We conducted a retrospective study of 60 patients with cutaneous rosacea. This study was approved by the ethics committee of the local hospital (2018/002-003), and all patients provided verbal and written informed consent before participating in the study. The study was carried out according to the guidelines of the Declaration of Helsinki.

Patient Selection and Evaluation
Patients diagnosed with rosacea by a dermatologist within 6 months were included in the study. Diagnosis of the disease was made after a detailed anamnesis and dermatologic examination. Rosacea was diagnosed if patients had an itching sensation, erythema and/or erythema attacks, and papules and pustules, and fulfilled the diagnostic criteria according to the National Rosacea Society. The skin disease was classified according to the subtypes as ETR, PPR, phymatous rosacea, or ocular rosacea.

The standard skin surface biopsy method was used in 60 patients for detecting Demodex density. When more than 5 mites were detected per square centimeter, the result was recorded as positive. Thirty consecutive, newly diagnosed patients with cutaneous acne rosacea with Demodex infestation and 30 consecutive, newly diagnosed sex- and age-matched patients with acne rosacea without Demodex infestation admitted to the dermatology outpatient clinic were included to this study. The patients who did not have any known dermatologic, systemic, or ocular diseases were included in the study. Patients who met any of the following criteria were excluded from the study: prior anti-inflammatory topical and/or systemic treatment for rosacea during the last 3 months, contact lens wear, eyelid surgery, or autoimmune disease requiring treatment.


Next Article: