The IASPs Classification of Chronic Pain does not have a diagnosis that corresponds to AFP, although it is listed in the differential diagnosis of "Glossodynia and sore mouth" (Burning mouth syndrome). However, in another IASP publication from 2011, the term PIFP is used and defined almost identically to the above. Despite the controversy surrounding the use of the term, it has a long history, and it is still in common use by clinicians to refer to chronic facial pain that does not meet any diagnostic criteria and does not respond to most treatments. Re-classification of trigeminal neuralgia
Trigeminal neuralgia is another example of a cause of facial pain. Neuralgia refers to pain in the distribution of a nerve (or nerves), and commonly implies paroxysmal (sudden) pain, although the accepted IASP definition specifies that the term should not be restricted to mean paroxysmal pain. Classic trigeminal neuralgia refers to sudden, shooting pain in the face, which is usually short lived and brought on by accidental stimulation of trigger points on the face, as may occur when washing. Trigeminal neuralgia has been described as one of the most painful conditions possible. Trigeminal neuralgia and AFP are traditionally considered separate, since AFP typically involves constant, often burning pain and trigeminal neuralgia classically shows paroxysmal, shooting pain, but in reality there is some overlap in their features. In 2005 researchers proposed a new classification of trigeminal neuralgia which described a type of trigeminal neuralgia where the pain was constant and burning.
Terms oligospermia, oligozoospermia, and low sperm count refer to semen with a low concentration of sperm and is a common finding in male infertility. Often semen with a decreased sperm concentration may also show significant abnormalities in sperm morphology and motility (technically oligoasthenoteratozoospermia). There has been interest in replacing the descriptive terms used in semen analysis with more quantitative information. Diagnosis
The diagnosis of oligozoospermia is based on one low count in a semen analysis performed on two occasions. For many decades sperm concentrations of less than 20 million sperm/ml were considered low or oligospermic, recently, however, the WHO reassessed sperm criteria and established a lower reference point, less than 15 million sperm/ml, consistent with the 5th percentile for fertile men. Sperm concentrations fluctuate and oligospermia may be temporary or permanent. Sources usually classify oligospermia in 3 classes:
Mild: concentrations 10 million – 15 million sperm/mL
Moderate: concentrations 5 million – 10 million sperm/mL
Severe: concentrations less than 5 million sperm/mLThe diagnosis of oligozoospermia requires a work-up via semen analysis (listed in Male infertility). Causes
There are many causes for oligospermia including:

Pre-testicular causes
Pre-testicular factors refer to conditions that impede adequate support of the testes and include situations of poor hormonal support and poor general health including:

Hypogonadism due to various causes
Drugs, alcohol, smoking
Strenuous riding (bicycle riding, horseback riding)
Medications, including androgens. Testicular factors
Testicular factors refer to conditions where the testes produces semen of poor quality despite adequate hormonal support and include:

Age
Genetic defects on the Y chromosome
Y chromosome microdeletions
Abnormal set of chromosomes
Klinefelter syndrome
Neoplasm, e.g.