A previously healthy 32 year-old woman presents with complaints of six months of worsening dry eyes and dry mouth. She feels a gritty sensation in her eyes, and has been unable to wear her contact lenses. She states her dentist is concerned because she has developed multiple dental caries. She also feels some fullness in her cheeks. She has been very fatigued and achy. Her physical exam reveals dry mucous membranes, dental caries at the gum line and swelling in her parotid glands. A Shirmer's test is done and results in 3 mm of bilateral tear wetting in 5 minutes. The remainder of the examination is normal. Laboratory testing is done and the ANA is 1:640 (by immunofluorescence), and the anti-Ro (SSA) and anti-La (SSB) antibodies are strongly positive. A diagnosis of primary Sjogren's syndrome (SS) is made.

What are the key features that lead to a diagnosis of SS?

Patients with primary SS commonly present with sicca symptoms (dryness), both ocular and oral. Persistent dry eyes and/or dry mouth (daily for over three months), without an alternative explanation are very important clues in this diagnosis. Patients describe a sandy or gravel sensation in their eyes. In addition to dryness (xerostomia), common oral complaints include salivary gland swelling, an increase in dental caries at the gum-line, and the need to use liquid to aid in swallowing or awakening at night to drink.

Ocular signs, such as a positive Schirmer's test can help give objective evidence for ocular dryness. A Schirmer's test can be done in the office and consists of gently placing sterile filter paper between the eye and the lower lid and measuring tear production. A positive test result is < 5 mm of wetting in 5 minutes. Additional tests include an ocular staining score (OSS), which involves fluorescein staining of the cornea and lissamine green staining of the bulbar conjunctivae for a total score ranging from 0-12 (> 3 is positive), and a tear breakup time (TBUT) of<10 seconds. Rose Bengal staining can be used to assess conjunctival and corneal damage in patients with sicca, but it is toxic to the epithelial cells and painful to patients.

Tests can also be done for xerostomia. These include salivary gland scintigraphy, which gives a dynamic measure of salivary gland function by looking at radiotracer uptake, and unstimulated whole salivary flow (UWS) which measures the rate of saliva production.

The presence of antibodies to Rheumatoid Factor (RF), ANA, Ro (SS-A) and La (SS-B) are commonly found in patients with primary SS. Multiple studies have reported differing frequencies, but in general the presence of one or more of these antibodies are seen in over half of affected patients.

A minor salivary gland biopsy is done with a punch biopsy of the lower lip to support a diagnosis of SS. A scoring system is employed by the pathologist, looking for focal lymphocytic sialadenitis (FLS), and a score of > 1 is considered positive.