This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immune system, Subject name: Medicine
Following are features of reactive ahritis except 
Select and explain. 
A. Acute non purulent assymetrical ahritis, B. Predominately affects upper extremities, C. Circinate balanitis is a distinctive feature, D. Associated with periahritis
B: Predominately affects upper extremities
Answer: B: Predominately affects upper extremities 
Explanation: Reactive ahritis refers to acute nonpurulent ahritis complicating an infection elsewhere in the body.The clinical manifestations of reactive ahritis constitute a spectrum that ranges from an isolated, transient monoahritis or enthesitis to severe multisystem disease. A careful history will usually elicit evidence of an antecedent infection 1-4 weeks before onset of symptoms of the reactive disease, paicularly in postenteric reactive ahritis.The joints of the lower extremities, especially the knee, ankle, and subtalar, metatarsophalangeal, and toe interphalangeal joints, are most commonly involved.Reactive ahritis shares many features in common with psoriatic ahropathy. However, it differs in:-PSORIATIC AHRITISREACTIVE AHRITISGradual in onsetAcutePrimarily in upper extremitiesLower extremitiesLess associated periahritisPeriahritisUsually no associated mouth ulcers, urethritis or bowel symptomsUsually no associated mouth ulcers, urethritis or bowel symptoms Harrison 19e 2175