====== Episcleritis ======
  * Self-limited inflammation of the episcleral layers (loose connective tissue layers with a vascular plexus between the conjunctiva and the sclera that are contiguous with Tenon's capsule) 
  * Female Adults more common than Male adults and both more common than in children
  * More common in boys than girls 
  * 50% may have a concurrent eye disease 


===== Associated Conditions =====
  * Collagen Vascular Diseases
    * Rheumatoid Arthritis (most common)
    * Chron's disease
    * Ulcerative colitis
    * Psoriatic arthritis
    * Systemic lupus erythematosis
    * Reactive arthritis (Reiter syndrome)
    * Relapsing polychondritis
    * Ankylosing spondylitis
    * Pustulotic artho-osteitis
  * Vasculitis
    * Polyartitis Nodosa
    * Temporal Arteritis 
    * Cogan Syndrome
    * Churg-Strauss Syndrome
    * Granulomatosis with polyangiitis
    * Bechet Disease
  * Dermatologic disease
    * Rosacea
    * Pyoderma gangrenosum
    * Sweet syndrome
  * Metabolic disease
    * Gout
  * Atopic disease
  * Malignancies
    * T-cell leukemia
    * Hodgkin lymphoma
  * Ocular 
    * Foreign bodies
    * Chemical injury
    * Infections
      * Mycobacteria
      * Spirochetes
        * Treponema 
        * Borrelia
      * Chlamydia
      * Actinomyces
      * Fungi
      * Virus
        * Herpes Zoster
        * Herpes Simplex
        * Mumps
        * Chikungunya
        * COVID-19
      * Protozoa
        * Acanthamoeba
        * Toxoplasma
        * Toxocara
  * Medications
    * Topiramate
    * Pamidronate

==== Work-Up ====
  * Consider if recurrent or other signs consistent with connective tissue disease (joint pain, fevers etc) vascular or dermatologic disease 
  * Possible testing:
    * Rheumatoid factor (Rheumatoid Arthritis)
    * Antinuclear antibody (collagen vascular disease)
    * Serum uric acid (gout),
    * Erythrocyte sedimentation rate (inflammation, vasculitis), 
    * Complete blood count with differential (infection, malignancy) 
    * VDRL/FTA-ABS (spirochete infection) 
    * Urinalysis 
    * PPD or Quantiferon Gold (mycobacteria)
    * Chest x-ray (mycobacgteria)
    * HLA-B27 (collagen vascular disease)