What is the differential diagnosis for dark circles around the eyes?

Differential Diagnosis for Dark Circles Around the Eyes

Dark circles around the eyes (periorbital hyperpigmentation) result from four primary mechanisms: allergic/inflammatory conditions, dermal pigmentation, vascular congestion, and structural shadowing from anatomical features.

Primary Etiologic Categories

Allergic and Inflammatory Causes

• Allergic rhinitis is the most common systemic association, with dark circles ("allergic shiners") occurring in up to 60% of atopic patients and representing periorbital hyperpigmentation from chronic venous congestion 1
• Atopic dermatitis produces Dennie-Morgan lines (infraorbital folds) in 60-80% of affected children, often accompanied by periorbital darkening 1
• Allergic conjunctivitis frequently coexists with allergic rhinitis, presenting with bilateral eyelid edema, periorbital hyperpigmentation, conjunctival injection, and watery discharge 2
• Chronic eye rubbing from allergic conditions causes postinflammatory hyperpigmentation and mechanical trauma to the delicate periorbital skin 2, 3

Pigmentary Causes

• Dermal melanin deposition appears as brown hyperpigmentation that becomes more prominent under Wood's lamp examination 3, 4
• Postinflammatory hyperpigmentation develops secondary to chronic dermatitis, particularly in darker skin types where melanocyte activity is more pronounced 5, 3
• Medication-induced dermatitis from topical ophthalmic medications (glaucoma drops, NSAIDs, antibiotics, antivirals) causes contact dermatitis with eyelid erythema, scaling, and secondary pigmentation 1

Vascular Causes

• Superficial vasculature creates blue-to-purple discoloration due to the thin periorbital skin allowing visualization of underlying vessels 3, 6
• Periorbital edema from fluid retention, sleep disturbances, or systemic conditions increases vascular congestion and shadowing 2, 3
• Venous pooling from chronic allergic inflammation leads to hemosiderin deposition and persistent discoloration 3

Structural/Anatomical Causes

• Tear trough deformity creates shadowing from the depression between the lower eyelid and cheek, accounting for structural-type dark circles 6, 7
• Infraorbital fat herniation (palpebral bags) produces shadows and was confirmed by ultrasonography in patients with prominent lower lid fullness 6
• Skin laxity and wrinkles cast shadows that appear as darkening, particularly with aging 3, 7
• Thin translucent skin overlying the orbicularis oculi muscle allows visualization of underlying structures, creating apparent darkness 7

Clinical Classification System

Research demonstrates that mixed-type dark circles (54%) are most common, followed by vascular type (35%), with pure pigmented (5%) and structural types (3%) being less frequent 4, 6. This finding is critical because it indicates most patients require multimodal assessment rather than single-cause attribution.

Associated Systemic Conditions

Rhinologic Disease

• Children with allergic rhinitis may present with sniffing, snorting, throat clearing, chronic mouth breathing, halitosis, dark circles under the eyes, and eye rubbing 2
• Nasal congestion and postnasal drainage frequently coexist with periorbital findings 2

Ocular Surface Disease

• Rosacea causes chronic blepharokeratoconjunctivitis with MGD, particularly in fair-skinned individuals, though it occurs in all skin types and may be difficult to diagnose in darker skin 2
• Dry eye syndrome exacerbates periorbital symptoms through chronic inflammation and frequent eye rubbing 2
• Dupilumab-associated ocular disease in patients treated for severe atopic dermatitis presents with bilateral injection and discharge 1

Recurrent Eyelid Infections

• Children with recurrent styes have increased risk of developing adult rosacea, which contributes to chronic periorbital inflammation 2

Critical Diagnostic Pitfalls

Do not assume dark circles are purely cosmetic without excluding underlying pathology. Dark circles may represent the final common pathway of dermatitis, allergy, systemic disorders, sleep disturbances, or nutritional deficiencies requiring medical intervention before aesthetic treatment 5.

Wood's lamp examination is essential to differentiate pigmented (brown, enhanced under Wood's lamp) from vascular (blue-purple, unchanged under Wood's lamp) causes 4, 6.

Unilateral presentation should raise concern for structural abnormalities, neoplasms, or localized inflammatory conditions rather than systemic allergic disease 2.