Can eczema present unilaterally, affecting only one eye?

Can Eczema Present Unilaterally on One Eye?

Yes, eczema (eczematous dermatitis) can absolutely present unilaterally affecting only one eye, though this presentation should prompt careful evaluation to exclude other important diagnoses, particularly sebaceous carcinoma and chronic blepharitis.

Key Diagnostic Considerations for Unilateral Eyelid Dermatitis

When Unilateral Presentation is Concerning

The American Academy of Ophthalmology emphasizes that marked asymmetry or involvement of only one eye with chronic blepharitis unresponsive to therapy should raise suspicion for carcinoma, particularly sebaceous carcinoma 1. This is a critical pitfall to avoid, as sebaceous carcinoma can masquerade as chronic unilateral blepharoconjunctivitis 1.

Red flags requiring biopsy include: 1

• Chronic unilateral presentation resistant to standard therapy
• Loss of normal eyelid margin anatomy
• Focal lash loss (ciliary madarosis)
• Unifocal recurrent chalazia not responding to treatment
• Conjunctival cicatricial changes in the affected eye

Eczema Can Be Unilateral

While eczema commonly affects both eyes, allergic contact dermatitis—the most common cause of eyelid dermatitis—can present unilaterally 2. In a study of 203 patients with eyelid dermatitis, 74% had relevant allergic contact dermatitis, and unilateral presentations occurred when exposure was asymmetric 2.

Common triggers for unilateral eyelid eczema include: 2

• Cosmetics applied asymmetrically
• Topical medications (including corticosteroids and eye drops)
• Metals (from eyeglass frames or jewelry)
• Artificial nails (transferred by hand-to-eye contact on one side)
• Occupational exposures affecting one side

Differential Diagnosis for Unilateral Eye Involvement

Infectious Causes to Consider

Several infectious conditions characteristically present unilaterally and must be distinguished from eczema:

Herpes simplex virus (HSV) conjunctivitis typically presents unilaterally with bulbar conjunctival injection, watery discharge, and mild follicular reaction, often with vesicular rash or ulceration of the eyelids 1, 3. The presence of vesicular lid lesions and dendritic corneal lesions are highly suggestive 3.

Molluscum contagiosum is typically unilateral, presenting with chronic follicular conjunctivitis and distinctive shiny, dome-shaped umbilicated lesions on the eyelid skin or margin 1.

Varicella zoster virus (VZV) usually presents unilaterally with vesicular dermatomal rash or ulceration of eyelids, often with severe pain 1.

Neoplastic Causes (Critical Not to Miss)

Sebaceous carcinoma presents with unilateral intense bulbar conjunctival injection, conjunctival scarring, and may have mucopurulent discharge 1. It often has a history of multiple chalazion excisions and can invade the corneal epithelium 1.

Diagnostic Approach

Clinical Examination Priorities

For suspected eczema, look for: 2, 4

• Polymorphic lesions (erythema, papules, vesicles, scales, crusts)
• Pruritus (itch-scratch cycle)
• History of atopic conditions
• Bilateral involvement elsewhere on the body
• Response to emollients and topical corticosteroids

For suspected malignancy, perform: 1

• Complete ocular surface examination
• Assessment for conjunctival cicatricial changes
• Evaluation of eyelid margin architecture
• Documentation of any focal lash loss
• Biopsy if any red flags present (consultation with pathologist recommended for potential frozen sections and mapping for pagetoid spread)

Testing Strategy

Patch testing should be performed when allergic contact dermatitis is suspected, as it identifies relevant allergens in the majority of cases 2. Additional testing may include radioallergosorbent test (RAST), skin prick tests, and usage tests 2.

Biopsy is indicated when: 1

• Marked asymmetry exists
• Resistance to standard therapy occurs
• Unifocal recurrent chalazia are present
• Any signs of malignancy exist

Management Approach

For Confirmed Eczematous Dermatitis

First-line treatment consists of: 4, 5

• Liberal use of emollients and daily bathing with soap-free cleansers
• Topical corticosteroids for flare-ups
• Topical calcineurin inhibitors (pimecrolimus or tacrolimus) as adjunct therapy
• Patient education about allergen/irritant avoidance

Identify and eliminate triggers: 2

• Review all cosmetics, eye medications, and topical products
• Consider occupational exposures
• Evaluate for metal sensitivity from eyewear
• Assess for transfer from artificial nails or nail products

When to Refer

Immediate ophthalmology referral is warranted for: 1

• Any suspicion of malignancy
• Chronic unilateral presentation unresponsive to therapy
• Conjunctival cicatricial changes
• Corneal involvement

Clinical Pearls

Atopic dermatitis patients have increased risk of ocular complications including blepharitis, keratoconjunctivitis, and keratoconus 6. However, even among atopic patients, allergic contact dermatitis was found to be a common concurrent cause of eyelid dermatitis 2.

The bottom line: While unilateral eyelid eczema is possible and often represents allergic contact dermatitis, this presentation demands thorough evaluation to exclude sebaceous carcinoma and other serious conditions. When in doubt, biopsy.