Frequency Of Unexplained Fevers

What Causes Unexplained Fever?

Unexplained fever can have various causes, ranging in severity from 'minor' to 'generally fatal'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

Diagnose your symptoms now!
  • check your overall health status
  • let The Analyst™ find what's wrong
  • understand what's happening to your body

Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose unexplained fever, we could:

  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "unexplained fever" as a symptom.  Here are eight of many possibilities (more below):
  • Lupus (SLE)
  • Crohn's Disease
  • Juvenile Rheumatoid Arthritis
  • Epstein-Barr Virus
  • Ovarian Cysts
  • Chronic Infection
  • Non-Hodgkin's Lymphoma
  • Leukemia

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
pain when breathing
poor mental clarity
long term neck stiffness
chronic vomiting
slight abdominal fullness
frequent confusion/disorientation
meal-induced pain for 1-4 weeks
poor cold weather tolerance
frequent unexplained vomiting
occasional unexplained vomiting
poor bodily coordination
... and more than 110 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of unexplained fever:
Cause Probability Status
Ovarian Cysts 90% Confirm
Crohn's Disease 21% Unlikely
Chronic Infection 17% Unlikely
Leukemia 4% Ruled out
Non-Hodgkin's Lymphoma 1% Ruled out
Juvenile Rheumatoid Arthritis 0% Ruled out
Lupus (SLE) 0% Ruled out
Epstein-Barr Virus 0% Ruled out
* This is a simple example to illustrate the process

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

In the Metabolic Symptoms section of the questionnaire, The Analyst™ will ask the following question about frequency of unexplained fevers:
How often do you get unexplained fevers?
Possible responses:
→ Never / rarely / don't know
→ Occasionally - one or two per year
→ Frequently - several/many per year
Based on your response to this question, which may indicate either occasional unexplained fevers or frequent unexplained fevers, The Analyst™ will consider possibilities such as:

Fevers can occur due to associated bacterial, viral, or fungal infections.

Lupus, SLE (Systemic Lupus Erythematosus)

A less common but more serious constitutional feature of SLE is persistent fever.


Symptoms of malaria include fever and flu-like illness, including shaking chills, headache, muscle aches, and tiredness.

Ulcerative Colitis

In severe acute attacks there may be fever.

Concerned or curious about your health?  Try The Analyst™
Symptom Entry
Symptom Entry
Full Explanations
Optional Doctor Review
Review (optional)