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Ophthalmia nodosa secondary to caterpillar-hair-induced conjunctivitis in a child

Published:December 23, 2019DOI:https://doi.org/10.1016/j.jcjo.2019.10.001
      Ophthalmia nodosa is an inflammatory reaction in and around the eyes to certain types of insect and plant hairs possessing unique characteristics, including mechanical and toxic attributes.
      • Joshi D.
      Ophthalmia nodosa with intraocular caterpillar setae.
      ,
      • Sridhar M.S.
      • Ramakrishnan M.
      Ocular lesions caused by caterpillar hairs.
      We recommend that ophthalmologists and paediatricians be informed of the potential complications from direct contact with these insects.
      A 6-year-old boy who had a black-and-orange-striped caterpillar thrown into his right eye by his older brother presented with conjunctival redness, swelling, pain, and decreased vision (Fig. 1A). The visual acuity was 20/80 in the right eye and 20/20 in the left eye. Numerous caterpillar hairs were embedded in the periocular skin, eyelids, and the palpebral and bulbar conjunctiva of the right eye.
      Fig 1
      Fig. 1Clinical photographs. (A) Inferior palpebral conjunctiva is injected with a follicular reaction in the right eye. (B) Thin caterpillar hair is embedded in the caruncle (black arrow).
      Initial attempted removal of the caterpillar hairs with forceps was technically difficult; the hairs were very fine and brittle such that the residual hair shaft remained deeply embedded in the anterior ocular tissues, causing continued irritation. The number of embedded hairs was estimated to be 50–100. Several attempts were made to remove as many hairs as possible under topical anaesthesia. However, the patient's symptoms persisted, and most of the remaining foreign bodies were eventually removed under general anaesthesia. Residual hairs were found in the deep palpebral conjunctiva superonasally, at the caruncle, and plica semilunaris (Fig. 1B). The protruding hairs were excised. Lack of fluorescein staining confirmed no corneal abrasions.
      Three weeks after the injury, 2 hairs remained embedded in the inferotemporal palpebral conjunctiva and 2 more in the caruncle/plica. All were subepithelial and the patient was asymptomatic.
      Histopathological examination of a conjunctival biopsy specimen disclosed a fragment of inflamed fibrous tissue (Fig. 2A) that contained an occasional multinuclear, foreign-body-type, giant cell (Fig. 2B), with focal infiltrates of lymphocytes, plasma cells, and macrophages, staining with CD68 (Fig. 2C). Light microscopic examination of a nonfixed hair from a different caterpillar of the same species showed a dark hair shaft with multiple, regularly placed pointed barbs aligned in the same direction protruding at about 30° acute angles (Fig. 3A). In deeper conjunctival specimen sections, a round, light brown structure with an inner tubule and outer barb-like projections was visualized, consistent with a caterpillar hair (Fig. 3B, C).
      Fig 2
      Fig. 2Histopathologic photomicrographs of conjunctival nodule. (A) Conjunctival tissue surrounds an empty space where a caterpillar hair had been embedded. Hematoxylin and eosin, original magnification × 25. (B) A multinuclear giant cell (arrow) near the area that harboured the hair. Hematoxylin and eosin, original magnification × 600. (C) Macrophages stain brown around area of prior foreign body. CD68, original magnification × 200.
      Fig 3
      Fig. 3Caterpillar hair characteristics. (A) Light microscopic examination of an unstained caterpillar hair reveals dichotomous 30° acute-angled barb-like projects along the shaft. Original magnification × 400. (B) Round caterpillar hair with external outer barb-like projections (arrow), and (C) the inner tubule is well delineated. Vimentin, original magnifications × 200 and × 1600, respectively.
      Caterpillar setae injuries, although uncommon, are a known cause of ophthalmia nodosa leading to a variety of ocular disorders, such as keratoconjunctivitis, conjunctival nodules, iridocyclitis, iris nodules, vitritis, papillitis, chorioretinopathy, endophthalmitis, and panophthalmitis.
      • Sridhar M.S.
      • Ramakrishnan M.
      Ocular lesions caused by caterpillar hairs.
      ,
      • Gundersen T.
      • Heath P.
      • Garron L.K.
      Ophthalmia nodosa.
      The pathophysiology of the inflammation is believed to have a dual etiology related to the mechanical progression of the hairs into the ocular tissues, as well as contact with a toxic protein extruded from the central venom gland within the caterpillar hair shaft.
      • Sridhar M.S.
      • Ramakrishnan M.
      Ocular lesions caused by caterpillar hairs.
      ,
      • Gundersen T.
      • Heath P.
      • Garron L.K.
      Ophthalmia nodosa.
      ,
      • Ascher K.W.
      Mechanism of locomotion observed on caterpillar hairs.
      The hairs possess barb-like projections directed toward the distal tip, allowing for forward penetration while making extraction against the direction of the barbs extremely difficult.
      • Shibui H.
      • Kawashima H.
      • Kamata K.
      • Sasaki H.
      • Inoda S.
      • Shimizu H.
      Vitrectomy for caterpillar seta-induced endophthalmitis.
      Furthermore, movement of the globe with respiration, heartbeat, and iris movement are proposed to propel the spines inward as the hairs themselves do not have propulsive power.
      • Gundersen T.
      • Heath P.
      • Garron L.K.
      Ophthalmia nodosa.
      The surrounding inflammatory exudates also have been suggested to allow the hairs to pass into the ocular structures along the path of least resistance.
      • Ascher K.W.
      Mechanism of locomotion observed on caterpillar hairs.
      Ophthalmia nodosa has a seasonal incidence that depends on the life cycle of the insect.
      • Gundersen T.
      • Heath P.
      • Garron L.K.
      Ophthalmia nodosa.
      The caterpillar in this case was of the Pyrrharctia isabella species, commonly known as the “woolly bear caterpillar,” with its larval stage during autumn, at which time our patient presented.
      A classification system outlining the ocular manifestations associated with caterpillar hair injuries has been proposed by Cadera et al,
      • Cadera W.
      • Pachtman M.A.
      • Fountain J.A.
      • Ellis F.D.
      • Wilson II, F.M.
      Ocular lesions caused by caterpillar hairs (ophthalmia nodosa).
      which includes the following:
      Type 1: an acute toxic reaction lasting from days to weeks causing inflammation, chemosis, foreign-body sensation, and epiphora
      Type 2: a chronic mechanical keratoconjunctivitis with hairs in the bulbar/palpebral conjunctiva causing linear scratches on the cornea
      Type 3: formation of grey-yellow granulomatous nodules in the conjunctiva
      Type 4: penetration by the hair into the anterior segment causing intense iritis, which may result in iris nodules or a hypopyon
      Type 5: vitreoretinal involvement either through the anterior chamber or by transscleral migration; vitritis, cystoid macular edema, papillitis, endophthalmitis, or panophthalmitis may occur
      The treatment for types 1 and 2 includes irrigation and removal of the hairs with administration of topical antibiotics and steroids, as in our patient. Type 3 may require surgical excision of the nodules. Topical steroids with or without operative removal of the hairs or an iridectomy for nodule excision may be warranted in type 4. Local and/or systemic corticosteroids with antibiotics, as well as vitrectomy with removal of the hairs, may be required for type 5, along with careful follow-up for subsequent infection or inflammation, which would require appropriate management.
      Our case demonstrated type 3 ophthalmia nodosa with the formation of a conjunctival granuloma surrounding the caterpillar hair. Slit-lamp examination did not reveal any hairs embedded in the cornea or penetrating into the anterior chamber, a finding that carries the potential for devastating outcomes.
      • Horng C.T.
      • Chou P.I.
      • Liang J.B.
      Caterpillar setae in the deep cornea and anterior chamber.
      • Rishi P.
      • Agarwal M.
      • Mahajan S.
      • Rishi E.
      Management of intralenticular caterpillar setae.
      • Sengupta S.
      • Reddy P.R.
      • Gyatsho J.
      • Ravindran D.R.
      • Thiruvengadakrishnan
      • Vaidee V.
      Risk factors for intraocular penetration of caterpillar hair in ophthalmia nodosa: a retrospective anaylysis.
      • Agarwal M.
      • Acharya M.
      • Majumdar S.
      • Paul L.
      Managing multiple caterpillar hairs in the eye.
      Patients should be advised to never rub the eyes once a caterpillar injury has occurred, and to seek medical treatment immediately. If removal of the hairs is not successful in the clinic, general anaesthesia may be required for the subsequent extirpation of residual hairs, which can easily be missed, and otherwise can continue to penetrate into the ocular structures, resulting in further damage and irritation.

      Footnotes and Disclosure

      The authors have no proprietary or commercial interest in any materials discussed in this article.

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