Phlyctenular keratoconjunctivitis is an inflammatory syndrome caused by a delayed (aka type-IV) hypersensitivity reaction to one or more antigens. The triggering antigen is usually a bacterial protein (particularly from ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often positive ...

''), but may also be a virus, fungus (particularly '' Candida albicans''), or

nematode The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...

Symptoms

* Irritation * Discomfort or pain * Foreign-body sensation * Tearing *

Blepharospasm Blepharospasm is any abnormal contraction of the orbicularis oculi muscle. The condition should be distinguished from the more common, and milder, involuntary quivering of an eyelid, known as myokymia, or fasciculation. In most cases, blepharosp ...

* Photophobia * Mucopurulent discharge (rarely) In cases where the cornea is affected, pain and photophobia are more likely, and corneal scarring can occur (potentially impairing vision).

Presentation

The syndrome is marked by the appearance of characteristic lesions, known as phlyctenules, on the cornea and/or conjunctiva. These usually manifest as small (1 - 3 or 1 - 4 mm) raised nodules, pinkish-white or yellow in color, which may ulcerate (or, more rarely, necrose) and are often surrounded by dilated blood vessels. Corneal lesions are usually triangular in shape, with the base at the limbus and the apex pointing towards the center of the cornea.

Diagnosis

Clinical findings of Corneal lesion or corneal ulceration.

Treatment

The symptoms of phlyctenular keratoconjunctivitis are primarily treated with application of an appropriate

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involv ...

eye drop, such as prednisolone acetate (Pred Forte) or loteprednol (Lotemax). Loteprednol is increasingly preferred due to its lower risk of elevating intraocular pressure. The corticosteroid suppresses the immune response, reducing inflammation and improving most symptoms. The causative agent (i.e. the source of the antigen that triggered the hypersensitive immune response) should also be identified. ''

'' is usually the primary suspect, along with ''

Mycobacterium tuberculosis ''Mycobacterium tuberculosis'' (M. tb) is a species of pathogenic bacteria in the family Mycobacteriaceae and the causative agent of tuberculosis. First discovered in 1882 by Robert Koch, ''M. tuberculosis'' has an unusual, waxy coating on its c ...

'' in areas where TB is endemic, followed by '' Chlamydia trachomatis''. Active bacterial infections may be treated with a

topical antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

or a combination antibiotic-steroid eye drop, such as

tobramycin/dexamethasone Tobramycin/dexamethasone, sold under the brand name Tobradex, is a fixed-dose combination medication in the form of eye drops and eye ointment, marketed by Alcon. The active ingredients are tobramycin (an antibiotic) and dexamethasone (a corticos ...

(Tobradex). An oral tetracycline antibiotic (such as

doxycycline Doxycycline is a broad-spectrum tetracycline class antibiotic used in the treatment of infections caused by bacteria and certain parasites. It is used to treat bacterial pneumonia, acne, chlamydia infections, Lyme disease, cholera, typhus, an ...

) may be used in systemic or particularly severe/intractable infections.

Erythromycin Erythromycin is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used duri ...

may be an effective alternative, especially in pediatric cases where the side effects of tetracyclines are unacceptable. Artificial tears can reduce dryness and discomfort from corneal lesions.

Photophobic Photophobia is a medical symptom of abnormal intolerance to visual perception of light. As a medical symptom photophobia is not a morbid fear or phobia, but an experience of discomfort or pain to the eyes due to light exposure or by presence o ...

discomfort can be mitigated with dark

sunglasses Sunglasses or sun glasses (informally called shades or sunnies; more names below) are a form of protective eyewear designed primarily to prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes. They can s ...

References

{{reflist Eye diseases

Symptoms

Presentation

Diagnosis

Treatment

See also

References