What are the potential complications of untreated blepharitis that I should be aware of in my practice?

Untreated blepharitis can lead to several potential complications that are important to recognise in clinical practice. These include the development of periorbital and orbital cellulitis, which are severe infections requiring emergency referral due to their sight- and life-threatening nature. Signs of these infections necessitate urgent hospital admission or same-day ophthalmology assessment, especially in children and adults with worsening symptoms or lack of improvement after initial treatment. Additionally, untreated blepharitis may cause corneal disease, presenting with pain, blurred vision, or rapid-onset visual loss, which also requires urgent referral. Chronic untreated blepharitis can mask or mimic malignant eyelid tumours such as sebaceous gland carcinoma, particularly if unilateral, persistent, and associated with features like lash loss, nodular masses, ulceration, or scarring. Such cases should prompt referral via a suspected cancer pathway. Furthermore, untreated blepharitis may be associated with or exacerbate other ocular surface conditions like dry eye disease, rosacea, and seborrhoeic dermatitis, complicating management. Persistent inflammation and poor control can lead to chronic symptoms and potential eyelid margin damage. Therefore, early recognition, ongoing treatment, and timely referral when complications or atypical features arise are essential to prevent these adverse outcomes NICE CKS.