Overview
- Definition
Ocular inflammation due to contact or penetration by hairs or setae of certain insects (e.g., caterpillars) and vegetables
- Five types
Type 1 – acute, anaphylactoid reaction consisting of conjunctival chemosis, inflammation, epiphora, and foreign body sensation
Type 2 – chronic mechanical keratoconjunctivitis caused by hairs lodged in bulbar/palpebral conjunctiva; linear scratches on cornea
Type 3 – formation of grayish-yellow asymptomatic conjunctival nodules
Type 4 – intense anterior uveitis due to hair penetration in anterior chamber; often associated with iris nodules and hypopyon
Type 5 – hair penetration into the vitreous and subretinal space; chorioretinal tracks pigmented with white, inflamed leading edge
Patients may develop some or all of the above features sequentially as hairs/setae migrate inwards, though most fall in types 1 and 2
- Symptoms
Redness
Photophobia
Foreign body sensation
Blurry vision
Floaters
- Laterality
Unilateral or bilateral
Course
Severity depends on the amount of hairs involved, but long-term prognosis is good in most cases.Type 1: acute and lasts for weeks
Type 2: chronic
Type 3: asymptomatic
Type 4: acute and severe
Type 5: may occur early or years after penetration
- Age of onset
All age groups affected
- Gender/race
No gender or racial predilection
- Systemic association
None
Exam: Ocular
Findings vary based on location of foreign materials
Anterior Segment
Chemosis (type 1)
Vertical abrasions of corneal epithelium: lid eversion reveals hair as dark spot with surrounding hyperemia near lid margin (type 2)
Conjunctival nodule (type 3)
Ciliary flush, anterior chamber inflammation, possible hypopyon, and iris nodules: hair visible in corneal stroma, iris, and adjacent trabecular band, or lens (type 4)
Posterior Segment (Type 5)
Setae/hairs in cortical vitreous
Mild-to-moderate vitritis
Snowballs/snowbanks
Yellow patches of retinochoroiditis (usually temporal macular area)
Macular edema
Papillitis
Exam: Systemic
Allergic dermatitis
Imaging
- Ultrasound Biomicroscopy (UBM)
Setae/hairs appear hyper-reflective
Localized swelling of iris and ciliary body
Laboratory and Radiographic Testing
None
Differential Diagnosis
Diffuse unilateral subacute neuroretinitis (DUSN)
Penetrating injury by other foreign materials
Treatment
Type 1: copious irrigation and topical steroids
Type 2: removal of hairs by forceps with lid eversion
Type 3: removal of conjunctival nodules (to prevent migration to cornea and subsequently other intraocular structures)
Type 4: topical steroids for keratitis and anterior uveitis; removal of hairs with forceps, iridectomy, and even lensectomy; neodymium:yttrium-aluminum-garnet (Nd:YAG) laser to disrupt hairs
Type 5: oral, periocular, or intraocular steroids for inflammatory control (but other infections must be ruled out before ocular injections); Nd:YAG laser to disrupt hairs; vitrectomy for resistant cases
Referral/Co-management
None