Palytoxin Keratitis

To identify the most common aetiology of palytoxin keratitis.   
To present the characteristic clinical manifestations of palytoxin keratitis, in our case caused by the regurgitation of crabs of the L-picor species found in the Loro Parque.
Presentation of the different therapeutic proposals for the management of this lesion in the early stages. In order to reduce the risk of persistent corneal leucoma with neovascularisation and conjunctival overgrowth, we highlight the systemic effects that the toxin can cause and insist on early but copious cleansing after contact with the toxin and prophylactic corticosteroid therapy.

A 40-year-old male patient presented to the Emergency Department (ED), referred by his general practitioner (GP), suspecting non-specific keratitis in a worker at Loro Parque. In association with this, the patient reported a metallic taste after handling L-Picor crabs. 
Medical history: Mite allergy.
Ophthalmological history: No reports. 

CVAM: 
- Left eye: 20/20.
- Right eye: 20/20.

IOP: 14/18 mmHg.

Slit lamp anterior segment:

- Left eye: Cornea clear, F-, Tyndall-, mixed hyperemia EFRON I, phakic. 
- Right eye: Cornea clear, F+ (annular infiltrate with some scattered bullae in the inferior hemicornea from 4 to 7 hours), Tyndall-, mixed hyperemia EFRON III, subtle Descemet's folds, phakic. Palpebral eversion showed hyperemic conjunctiva with multiple follicles (no papillae). 

Treatment: 
The initial treatment should always include the removal of the toxin from the eye by means of irrigation or the instillation of artificial tears. Furthermore, because of the high risk of bilateral symptoms, the literature stresses the need to irrigate both eyes. 

Following extensive initial irrigation, early treatment with topical medium-potency steroids is recommended (for us, 1 drop of prednisolone acetate 1% every 6 hours) with concomitant antibiotic prophylaxis (for us, 1 drop of ofloxacin every 6 hours). In moderate/severe cases, a schedule of 1% prednisolone acetate in combination with oral steroids, oral doxycycline and ascorbic acid is recommended. 

Palytoxin (PTX) is a toxin that is commonly found in zoanthids (i.e. soft corals) of the genus Palythoa.

The inhalation of vapours when cleaning or removing corals from home aquariums is most commonly associated with exposure to PTX and the resulting toxicity.

IMPORTANT ANALYSIS: Careful history taking is essential in the assessment of exposure to PTX as the diagnosis is clinical.

Conjunctival hyperemia with or without an annular inflammatory infiltrate associated with Descemet's membrane folding is the most commonly described.

Early treatment with medium-potency topical corticosteroids and associated prophylactic antibiotic therapy is recommended after an initial copious irrigation.