Differentials
Chlamydial inclusion conjunctivitis
SIGNS / SYMPTOMS
Generally occurs in adults not living in areas where trachoma is endemic.
INVESTIGATIONS
Swab culture detects genital strains of Chlamydia trachomatis.
Viral conjunctivitis
SIGNS / SYMPTOMS
A common cause of conjunctival follicles.
It can be distinguished from trachoma by an acute history and mucopurulent discharge.
Herbert's pits or pannus are absent.
Both conditions may lead to tarsal conjunctival scarring.
INVESTIGATIONS
A swab for HSV and adenovirus could be considered.
Bacterial conjunctivitis
SIGNS / SYMPTOMS
Bacterial infection such as Moraxella can be a rare cause of follicle formation.
Absence of Herbert's pits.
INVESTIGATIONS
Microscopy, culture, and sensitivity testing on a conjunctival swab may reveal a bacterial cause.
Hypersensitivity conjunctivitis
SIGNS / SYMPTOMS
A careful history may reveal exposure to allergens (e.g., chronic exposure to drugs or eye cosmetics).
Absence of Herbert's pits.
INVESTIGATIONS
If conjunctival swab is performed, the culture is negative for hypersensitivity conjunctivitis.
Vernal conjunctivitis
SIGNS / SYMPTOMS
As an allergic disorder, patients often have associated atopy.
Symptoms include itching, lacrimation, photophobia, foreign body sensation, and burning.
Appearance of everted conjunctiva is ‘cobblestone’ and different from the characteristic follicles of trachoma.
Absence of Herbert's pits.
INVESTIGATIONS
Giemsa cytology of conjunctival scrapings shows many eosinophils.
Parinaud oculoglandular syndrome
SIGNS / SYMPTOMS
This rare ophthalmic condition may also cause follicles.
There may be an associated condition such as cat-scratch fever, tuberculosis, syphilis, lymphogranuloma venereum, or glandular fever.
Absence of Herbert's pits.
INVESTIGATIONS
Specific tests are required for each suspected associated condition, depending on history and clinical setting.
Trauma or chemical injury to eye
SIGNS / SYMPTOMS
History of trauma or chemical contact with eye.
Both conditions may lead to tarsal conjunctival scarring.
Absence of Herbert's pits.
INVESTIGATIONS
Differentiated clinically.
Stevens-Johnson syndrome
SIGNS / SYMPTOMS
Other signs and symptoms typically include the sudden appearance of a rash or a rash appearing after a new medicine has been commenced.
Both conditions may lead to tarsal conjunctival scarring.
Absence of Herbert's pits.
Trachoma is more likely in an area where it is endemic.
INVESTIGATIONS
Differentiated clinically.
Ocular cicatricial pemphigoid
SIGNS / SYMPTOMS
Pemphigoid has scarring in the bulbar conjunctiva and the plica; trachoma may show Herbert's pits in the superior cornea.
Both conditions may lead to tarsal conjunctival scarring.
Trachoma is more likely in an area where it is endemic.
INVESTIGATIONS
Differentiated clinically.
Idiopathic trichiasis
SIGNS / SYMPTOMS
May be difficult to differentiate clinically from trichiasis due to trachoma, although it is unlikely to have tarsal scarring.
Absence of Herbert's pits.
Trachoma is more likely in an area where it is endemic.
INVESTIGATIONS
Differentiated clinically.
Trichiasis due to other chronic inflammatory conditions
SIGNS / SYMPTOMS
Trichiasis can be idiopathic or secondary to a large range of chronic inflammatory diseases such as blepharitis and chronic conjunctivitis.
Absence of Herbert's pits.
Trachoma is more likely in an area where it is endemic.
INVESTIGATIONS
Differentiated clinically.
Corneal opacity due to other causes
SIGNS / SYMPTOMS
There are many other causes of corneal opacity.
However, when seen in conjunction with trichiasis and other signs of trachoma in a patient who has spent a significant amount of their life in a trachoma-endemic area, a diagnosis of trachomatous corneal opacity is likely.
INVESTIGATIONS
Differentiated clinically.
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