[Chronic mucosynechial pemphigoid: so-called ocular pemphigus]

Area of Science:

• Ophthalmology
• Dermatology
• Pathology

Background:

• Ocular pemphigus, now recognized as chronic mucosynechial pemphigoid (CMSP), is an oculocutaneomucosal disease with a long history of clinical observation.
• Its classification as a distinct nosological and histopathological entity is relatively recent, following extensive debate and comparison with other bullous dermatoses.

Observation:

• Ocular manifestations include progressive conjunctival scarring, symblepharon, entropion, and trichiasis, often leading to xerosis and a 'statute eye' appearance.
• Corneal complications such as bullous eruptions and erosions can occur, alongside potential skin and mucous membrane lesions, though systemic health typically remains unaffected.
• Advanced stages may present with a 'pemphigoid facies'.

Findings:

• Histopathological examination reveals a characteristic sub-epidermic bulla, differentiating CMSP from pemphigus vulgaris, which features intra-epidermal bullae.
• Conjunctival and other mucous membrane lesions show epithelial changes, increased glycogen and DNA in the Malpighian layer, and dermal infiltration by inflammatory cells.
• Significant findings include increased hyaluronic acid in the dermis, dermoepidermal separation, basal membrane alterations, and occasionally hyaluronic acid lumps within bullae.

Implications:

• The distinct histopathological features of CMSP warrant early diagnostic biopsy in suspected cases.
• Understanding the sub-epidermic bulla formation and dermal changes is crucial for accurate diagnosis and differentiating CMSP from other conditions.
• Further research into the debated viral and autoimmune etiologies of CMSP is necessary for developing targeted therapies.