Clinical Conditions of the Eyelids and Lashes

Vocabulary flashcards covering clinical definitions, etiology, presentation, and complications of disorders affecting the eyelashes and eyelids.

Eyelash ptosis

Misdirection of the superior eyelashes where they point downward, caused by laxity of eyelid structures such as the orbicularis oculi or tarsal plate.

Trichomegaly

Excessively long, thick, or deeply pigmented eyelashes, defined as lashes exceeding $12\,mm$ in length.

Madarosis

Loss or thinning of eyelashes resulting from hair follicle scarring (seen with malignant eyelid tumors) or non-scarring conditions (such as atopic dermatitis).

Poliosis

Whitening or depigmentation of the eyelashes or eyebrows caused by destruction of melanocytes at the base of the hair follicle.

Trichiasis

An acquired abnormality where normally positioned eyelashes are misdirected backwards toward the globe.

Distichiasis

An extra row of eyelashes emerging from the orifices of the meibomian glands, occurring when sebaceous glands become pilosebaceous units.

Anterior blepharitis

Inflammation of the eyelid margin anterior to the meibomian glands, presenting as staphylococcal (with collarettes at the lash base) or seborrheic (with greasy lid margins and matted lashes).

Angular blepharitis

Eczematoid inflammation localized to the lateral or medial canthus, caused by Staphylococcus aureus (dry, scaly skin) or Moraxella lacunata (wet, macerated skin with white frothy discharge).

Posterior blepharitis

Inflammation of the meibomian glands and posterior lid margin characterized by meibomian gland capping, thickened meibum expression, lid hyperemia, and an oily/frothy tear film.

Phthiriasis palpebrarum

Parasitic infection of the eyelashes caused by pubic lice (Pediculosis pubis), characterized by lice anchored to the lashes and small brownish opalescent nits.

Demodex folliculorum

Parasitic mite infection residing in eyelash hair follicles that presents with cylindrical dandruff at the base of short, thin lashes.

Demodex brevis

Parasitic mite infection residing deep within the meibomian glands, presenting with meibomian gland capping and posterior lid inflammation.

External hordeolum

Acute localized bacterial infection of a Gland of Zeis or Gland of Moll along the eyelid margin, presenting as a painful, hyperemic pustule.

Internal hordeolum

Acute localized bacterial infection of a meibomian gland, presenting with localized pain, heat, and swelling within the tarsal plate without an external pustule on the lid margin.

Preseptal cellulitis

Bacterial infection of the subcutaneous tissue anterior to the orbital septum, presenting with eyelid swelling, redness, warmth, and pain without affecting extraocular movements or vision.

Orbital cellulitis

Life-threatening bacterial infection of the soft tissues posterior to the orbital septum, characterized by proptosis, pain with eye movements, double vision, and potential vision loss.

Blepharochalasis

Rare condition characterized by recurrent, painless, non-pitting edema episodes of the eyelids, leading to thin, wrinkled, redundant skin and secondary ptosis.

Allergic edema

Bilateral periorbital eyelid swelling caused by an acute inflammatory hypersensitivity reaction to allergens, presenting with severe itching and conjunctival chemosis.

Contact dermatitis

Inflammatory skin condition triggered by direct exposure to topically applied irritants or allergens, presenting with eyelid hyperemia, severe itching, scaling, and chemosis.

Atopic dermatitis

Chronic inflammatory skin condition associated with asthma and hay fever, presenting with thickened, crusty, hyperemic eyelid skin and madarosis.

Herpes simplex eyelid dermatitis

Localized HSV-1 viral infection presenting with a prodromal tingling sensation followed by grouped periorbital vesicles and swelling that respects the facial midline.

Herpes Zoster Ophthalmicus

Reactivation of the Varicella Zoster Virus along the ophthalmic branch of the trigeminal nerve ($V_1$), presenting with a painful maculopapular rash respecting the facial midline.

Chalazion

Chronic, painless, sterile lipogranulomatous inflammatory lesion of a meibomian gland caused by obstructed lipid breakdown products leaking into eyelid tissue.

Sebaceous cell carcinoma

Aggressive malignancy of the sebaceous glands that often mimics a chronic or recurrent chalazion and causes lid margin thickening and madarosis.

Cutaneous horn

Hyperkeratotic, conical protrusion emerging from the skin or eyelid margin, arising from underlying benign, precancerous, or malignant lesions.

Pyogenic granuloma

Benign vascular growth of blood vessels triggered by trauma or surgery, presenting as a painful, bright red or purple polypoidal lesion that bleeds easily.

Keratoacanthoma

Fast-growing hair follicle tumor presenting as a dome-shaped nodule with a central keratin-filled crater, capable of transforming into Squamous Cell Carcinoma.

Moll cyst

Small, painless, translucent retention cyst arising from the apocrine sweat glands located along the anterior eyelid margin.

Zeis cyst

Small, painless, opaque white or yellow retention cyst arising from sebaceous Glands of Zeis on the anterior lid margin.

Milia

Tiny, white, round papules arising from pilosebaceous units occurring in clusters on the eyelid skin.

Eccrine hidrocystoma

Translucent retention cyst arising from eccrine sweat glands located on the eyelid skin away from the lid margin.

Squamous cell papilloma

Common benign skin tag composed of hyperplastic squamous epithelium with a vascular core, presenting as a soft, pedunculated or sessile lesion.

Verruca vulgaris

Benign viral eyelid wart caused by Human Papillomavirus (HPV), presenting as a skin-colored, waxy, or finger-like projection on the lid margin.

Molluscum contagiosum

Viral skin infection caused by a poxvirus, presenting as smooth, pale, waxy, umbilicated nodules along the eyelid margin.

Xanthelasma

Subcutaneous yellow lipid deposits situated near the medial canthus, associated in $50\%$ of cases with hypercholesterolemia or other systemic metabolic conditions.

Seborrheic keratosis

Common benign skin growth caused by proliferation of immature keratinocytes, presenting as a well-defined, slow-growing, greasy brown 'stuck-on' plaque.

Capillary hemangioma

Common benign pediatric vascular tumor presenting as a raised red or purple eyelid lesion that blanches with pressure and swells during crying.

Port-wine stain

Congenital dermal capillary malformation appearing as a flat pink-to-purple patch along the trigeminal nerve distribution that does not blanch with pressure.

Nevus of Ota

Congenital oculodermal melanosis presenting with slate grey-blue hyperpigmentation along $V_1$/$V_2$ branches and ipsilateral scleral hyperpigmentation.

Junctional nevus

Flat, pigmented plaque appearing in childhood with nevus cells confined to the dermal-epidermal junction.

Compound nevus

Elevated, papular, pigmented lesion appearing during puberty with nevus cells in both the junctional and dermal layers.

Intradermal nevus

Elevated, flesh-colored or lightly pigmented lesion appearing in adulthood with nevus cells confined entirely within the dermis.

Actinic keratosis

Flat, scaly, erythematous precancerous skin lesion caused by chronic UV exposure that serves as a direct precursor to Squamous Cell Carcinoma.

Basal cell carcinoma

The most common eyelid cancer, presenting as a firm, locally invasive nodule with pearly raised borders, central ulceration, and surface telangiectasia.

Squamous cell carcinoma

Invasive eyelid cancer arising from epidermal keratinocytes, presenting as a firm hyperkeratotic nodule or ulceration lacking surface telangiectasia.

Kaposi sarcoma

Vascular malignancy caused by Human Herpesvirus 8 (HHV-8) in immunocompromised patients, presenting as elevated purple eyelid or conjunctival lesions.

Merkel cell carcinoma

Rare, highly aggressive neuroendocrine skin cancer presenting as a painless, fast-growing red or pink upper eyelid nodule with a high rate ($30\%$) of metastasis.

Marcus Gunn jaw-winking syndrome

Congenital neurogenic ptosis caused by aberrant innervation of the levator muscle by the motor branch of the trigeminal nerve ($V_3$), resulting in upper lid retraction during jaw movements.

Pseudoptosis

False impression of eyelid drooping despite normal levator function and lid margin position, caused by dermatochalasis, lack of globe support, or contralateral lid retraction.

Dermatochalasis

Age-related excess, redundant, and lax upper or lower eyelid skin that sags over the lid margin and can obstruct the superior visual field.

Epiblepharon

Congenital condition where a horizontal fold of redundant skin and hypertrophied orbicularis muscle pushes the lower eyelashes inward against the globe while the eyelid margin remains normally positioned.

Entropion

Inward inversion of the eyelid margin toward the globe, causing eyelashes and skin to rub against the cornea.

Ectropion

Outward eversion of the eyelid margin away from the globe, exposing the palpebral conjunctiva and leading to tear evaporation and epiphora.

Lagophthalmos

Inability to fully close the eyelids, causing inferior scleral show during closure, exposure keratopathy, and nocturnal corneal drying.

Floppy eyelid syndrome

Bilateral condition characterized by extreme lid laxity and rubbery tarsal plates, causing spontaneous lid eversion during sleep; strongly associated with obstructive sleep apnea.

Blepharospasm

Involuntary, bilateral, forcible contraction or spasm of the orbicularis oculi and surrounding facial muscles.

Eyelid myokymia

Benign, self-limiting fine twitching of the orbicularis oculi muscle, typically triggered by stress, fatigue, or excess caffeine intake.

Epicanthal folds

Vertical skin folds covering the inner canthus, creating a false appearance of esotropia (pseudoesotropia) in infants or Asian individuals.

Congenital coloboma

Full-thickness notch or defect in the eyelid margin resulting from failure of embryological lid development and fusion.

Thyroid eye disease

Autoimmune inflammatory condition affecting orbital fat and extraocular muscles, presenting with upper eyelid retraction, lagophthalmos, proptosis, and extraocular muscle restriction.

Ocular rosacea

Chronic inflammatory condition affecting the eyelids and ocular surface, featuring meibomian gland capping, lid telangiectasia, and facial erythema.

Sturge-Weber syndrome

Congenital neurocutaneous disorder combining a facial port-wine stain along V1 with leptomeningeal vascular malformations, seizures, and glaucoma.