Reactive arthritis

Also known as Reiter's syndrome, is a form of inflammatory arthritis that develops in response to an infection in another part of the body (cross-reactivity). Coming into contact with bacteria and developing an infection can trigger the disease. By the time the patient presents with symptoms, often the "trigger" infection has been cured or is in remission in chronic cases, thus making determination of the initial cause difficult.
The arthritis often is coupled with other characteristic symptoms, called Reiter's syndrome.

Arthritis of large joints:
1. Monoarthritis affecting the large joints such as the knees and sacroiliac spine.
2. Arthritis of interphalangeal joints may be present but with relative sparing of small joints such as the wrist and hand.
Conjunctivitis or Uveitis
Urethritis / Prostatitis in men or Cervicitis / Salpingitis / Vulvovaginitis in women
1. Circinate balanitis in 20-40 % of the men

Patients can also present with mucocutaneous lesions, as well as psoriasis-like skin lesions such as circinate balanitis, and keratoderma blennorrhagicum.
Enthesitis can involve the Achilles tendon resulting in heel pain.
The clinical pattern of reactive arthritis commonly consists of an inflammation of fewer than five joints which often includes the knee or sacroiliac joint.
The arthritis may be "additive" or "migratory".

A small percentage of men and women develop small hard nodules called keratoderma blennorrhagicum on the soles of the feet and, less commonly, on the palms of the hands or elsewhere. The presence of keratoderma blennorrhagica is diagnostic of reactive arthritis in the absence of the classical triad. Subcutaneous nodules are also a feature of this disease.
Dactylitis, or "sausage digit", a diffuse swelling of a solitary finger or toe, is a distinctive feature of reactive arthritis and other peripheral spondylarthritides but can also be seen in polyarticular gout and sarcoidosis.
Mucocutaneous lesions can be present. Oral painless ulcers, Aphthous stomatitis, Geographic tongue and Migratory stomatitis
Crohn's disease.
Cardiac manifestations, including aortic regurgitation and pericarditis (10%)
Ankylosing spondylitis

Note that HSV-1 would be a good candidate but its ulcers are too painful. It does not cover Crohn's disease and Ankylosing spondylitis.
MTB covers all entities. Also there is good relation between Tuberculosis and Sarcoidosis
Therefore MTB would be a good candidate for Geographic tongue, Painless Aphthous stomatitis and Balanitis

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