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Freckle
Freckle (ephelis, ephelides): small brown macule on sun-exposed skin that darkens in summer and fades in winter, caused by uneven MC1R-linked melanin production; distinct from lentigines and moles, and a marker of skin cancer risk.
Fred Hutchinson Cancer Center
Fred Hutchinson Cancer Center (Fred Hutch), Seattle nonprofit formed April 1, 2022 by merging Fred Hutchinson Cancer Research Center (founded 1975) and Seattle Cancer Care Alliance; NCI comprehensive cancer center and UW Medicine's cancer program.
Frédéric Ferrière
Frédéric-Auguste Ferrière (1848–1924) was a Swiss physician and Red Cross vice-president who founded the civilian section of the International Prisoners-of-War Agency in Geneva during World War I.
Frederick D. Weber
Frederick D. Weber is an American technology executive who served as Chief Technology Officer of AMD from 1995 to 2005 and was elected to the National Academy of Engineering in 2005.
Free energy principle
Free energy principle (FEP), Karl Friston's theory of self-organizing biological agents: they minimize variational free energy, a bound on sensory surprise, via perception and active inference; corollary of Bayesian brain ideas, criticized as unfalsifiable.
Free flap surgery
Free flap surgery, or free flap reconstruction, moves a block of tissue such as skin, muscle, or bone to another part of the body, reconnecting its blood supply microsurgically.
Free sialic acid storage disease
Free sialic acid storage disease (FSASD), also called Salla disease in its mild form and ISSD in its severe form, is a rare autosomal recessive lysosomal storage disorder caused by SLC17A5 (sialin) defects, causing lysosomal sialic acid accumulation, hypomyelination, ataxia, and elevated urinary free sialic acid.
Free tissue transfer
Free tissue transfer is a reconstructive microsurgical procedure that moves skin, muscle, or bone with its blood supply to a distant site, reconnecting its vessels to recipient vessels.
Free water clearance
Free water clearance is a renal physiology measure of the rate at which the kidneys excrete or retain solute-free water, used to guide hyponatremia treatment.
Free-Rea study
FREE-REA study, a French prospective multicenter observational trial (NCT02450669) of 1514 extubations in 26 ICUs, 2013-2015; found 10.4% extubation failure, split into airway versus non-airway failure with distinct risk factors.
Freeganism
Freeganism is an anti-consumerist practice of salvaging discarded food, chiefly via dumpster diving, coined by a Food Not Bombs founder in the late 1990s; practitioners also squat, garden guerrilla-style, and avoid paid work.
Freeman-Sheldon syndrome
Freeman-Sheldon syndrome, also called Freeman-Burian or whistling face syndrome (DA2A), is a rare congenital distal arthrogryposis caused by MYH3 variants, marked by microstomia, pursed lips, H-shaped chin dimple, and hand and foot contractures.
Fregoli delusion
Fregoli delusion, or Fregoli syndrome, is a rare delusional misidentification syndrome in which a familiar person is believed to be disguising themselves as strangers; first described by Courbon and Fail in 1927, named after quick-change actor Leopoldo Fregoli, and linked to right-hemisphere frontal lesions in secondary cases.
Freiberg disease
Freiberg disease (Freiberg infraction, Freiberg-Köhler syndrome) is osteonecrosis of a metatarsal head, usually the second, in adolescent females (5:1 female ratio). Described by Freiberg in 1914; staged by Smillie I–V; treated conservatively first, then with osteotomy or osteochondral grafting.
Fremanezumab
Fremanezumab (Ajovy, Teva) is a humanized anti-CGRP monoclonal antibody for migraine prevention; FDA-approved 2018 for adults, 2025 for children 6–17, dosed 225 mg monthly or 675 mg quarterly.
Fremitus
Fremitus (vocal or tactile fremitus) is a voice-produced vibration palpated on the chest wall; increased over lung consolidation such as pneumonia, decreased over pleural effusion, pneumothorax, or emphysema, with low sensitivity but high specificity.
Frenectomy
Frenectomy (frenulectomy): complete surgical removal of an oral frenulum, related to frenotomy and frenuloplasty. Main indications are ankyloglossia with breastfeeding difficulty and aberrant labial frenum causing diastema or gingival recession; evidence for non-breastfeeding indications is weak.
Freneslerbart
Freneslerbart (freneslerbart/mevonlerbart, REGN1908-1909) is Regeneron's 1:1 cocktail of two fully human IgG4 monoclonal antibodies against the cat allergen Fel d 1, studied as single-dose passive immunotherapy for cat-allergic rhinitis and asthma.
Frenotomy
Frenotomy is a minor surgical procedure that divides the lingual frenulum, the tissue anchoring the tongue to the mouth's floor, to treat tongue-tie restricting breastfeeding in infants.
Frenulum
A frenulum (plural frenula, also frenum) is a small fold of tissue anchoring one movable body structure to another, found in the mouth, genitals, digestive tract, and brain.
Frenulum breve
Frenulum breve, or short frenulum, is a congenital or acquired shortening of the penile frenulum causing painful erections, tearing, and sometimes premature ejaculation; treated with stretching, steroid creams, or frenuloplasty.
Frenum piercing
A frenum piercing is a male genital piercing placed through the loose surface tissue on the underside of the penis shaft, second in popularity only to the Prince Albert.
Frequency spinal cord stimulation
Frequency spinal cord stimulation (SCS) is a neuromodulation therapy that delivers tonic electrical pulses to the spinal cord to relieve chronic, intractable pain of the trunk and limbs.
Frequent episodic tension-type headache
Frequent episodic tension-type headache (ICHD-3 2.2) is a primary headache with bilateral, pressing, mild-to-moderate attacks on 1-14 days/month for >3 months; treated with simple analgesics and, if disabling, preventives such as amitriptyline.
Frequent menstrual bleeding
Frequent menstrual bleeding (frequent menses, ICD-11 GA20.10) is a FIGO-defined abnormal uterine bleeding symptom: cycles shorter than 24 days, more than four episodes in 90 days, usually from ovulatory dysfunction.
Frequent micturition
Frequent micturition (urinary frequency, ICD-11 MF50.0) is urinating many times day or night in normal or small volumes, unlike polyuria (>3 L/day); common causes include UTI, BPH, incontinence, calculi, and overactive bladder.
Fresh frozen plasma
Fresh frozen plasma (FFP) is plasma frozen at −25°C or colder within 6–8 hours of separation, used to replace coagulation factors in bleeding, massive hemorrhage, and factor deficiencies; dose 10–20 ml/kg, thawed use within 24 hours.
Freshman 15
Freshman 15: the popular belief that first-year college students gain 15 pounds (6.8 kg). Research, including a 2015 meta-analysis, finds an average gain of about 1.36 kg (3 lbs), with only 9.3% gaining 15 pounds.
Frey syndrome
Frey syndrome (auriculotemporal syndrome, gustatory hyperhidrosis): gustatory sweating and flushing from aberrant parasympathetic regeneration after auriculotemporal nerve injury, usually parotidectomy; described by Lucja Frey, 1923.
Friction blister
Friction blister (ICD-11 EH92.1), an intraepidermal blister from repetitive shear deformation, typically in the stratum spinosum of palms, soles, and toes; treated by drainage and dressings, prevented by socks, insoles, and tape.