What is the pathophysiology of allergic shiners?

Pathophysiology of Allergic Shiners

Allergic shiners are caused by venous congestion beneath the eyes resulting from nasal obstruction and inflammation associated with allergic rhinitis. 1

Mechanism of Development

Allergic shiners appear as symmetrical, blue-grey discolorations of the periorbital skin, most apparent below the orbit. They develop through the following pathophysiological process:

1. Nasal Congestion and Venous Stasis

   • Allergic rhinitis causes significant nasal congestion
   • This congestion impairs normal venous drainage from the periorbital region
   • The resulting venous stasis beneath the eyes creates the characteristic dark discoloration 1

2. Inflammatory Process

   • The underlying allergic response begins with allergen processing by dendritic cells in the nasal mucosa
   • These cells present allergens to T-cell receptors, leading to TH2-biased cell proliferation
   • TH2 cells produce cytokines (IL-3, IL-4, IL-5, IL-13, GM-CSF) that drive the inflammatory cascade 2
   • This inflammation extends to affect periorbital venous flow

3. Vascular Changes

   • Increased vascularization of the nasal mucosa occurs in allergic patients
   • Studies show significantly higher vascular density (measured by CD31 expression) in allergic patients compared to non-allergic individuals 1
   • VEGF-C expression is also elevated in allergic rhinitis, promoting vascular proliferation 1
   • These vascular changes contribute to the congestion that leads to allergic shiners

Clinical Significance and Characteristics

• Allergic shiners occur in approximately 60% of atopic patients and 38% of non-atopic individuals 1
• They are typically associated with nasal congestion
• The darkness of allergic shiners correlates positively with:
  • Duration of allergic rhinitis
  • Severity of practical problems
  • Eye symptom severity 3
• Interestingly, the darkness and size of allergic shiners are paradoxically inversely correlated 3
• Allergic shiners tend to fade with increasing age 1

Quantitative Assessment

Recent research has developed computerized methods to quantify allergic shiners:

• Darkness of allergic shiners correlates with chronicity and severity of allergic rhinitis
• Shiners are darker in children with higher scores of eye symptoms and practical problems
• Larger shiners correlate with activity limitations and other symptoms 3

Differential Features

• Unlike edematous nasal mucosa, allergic shiners do not respond to topical vasoconstrictors
• They are often found in atopic family members
• They appear similar to the folds seen in patients with Down syndrome
• Allergic shiners should be distinguished from other causes of periorbital darkening such as fatigue, anemia, or hereditary factors 1

Clinical Implications

• The presence of allergic shiners can be a helpful diagnostic clue for allergic rhinitis
• Their severity may correlate with the overall burden of allergic disease
• Treatment of the underlying allergic rhinitis with intranasal corticosteroids may improve the appearance of allergic shiners by reducing nasal congestion and improving venous drainage 2

Understanding the pathophysiology of allergic shiners helps clinicians recognize this important physical finding and its relationship to the underlying allergic process.