Human health and medicine

Lip bite test

The lip bite test is a clinical maneuver in dentistry and orthognathic surgery used to assess lip competence, whether the lips can seal at rest without visible strain.

Lip fissure (ICD-11 DA00.3) is a split or crack in the lip, spanning chapped-lip cracks, angular cheilitis fissures, and chronic lip fissures; median lip fissure is hereditary and treated by excision with Z-plasty.

Lip licker's dermatitis

Lip licker's dermatitis, also called lip-lick cheilitis, is irritant contact dermatitis of the lips and perioral skin caused by habitual licking and saliva's digestive enzymes, common in school-aged children, worst in winter, treated with behavior change, emollients, and topical corticosteroids or calcineurin inhibitors.

Lip reconstruction

Lip reconstruction is the set of surgical methods used to repair full-thickness or partial defects of the upper or lower lip after trauma or, most commonly, resection of malignancy.

LIPE-related familial partial lipodystrophy

LIPE-related familial partial lipodystrophy (FPLD6, OMIM 615980) is a rare autosomal recessive lipodystrophy caused by LIPE mutations encoding hormone-sensitive lipase, causing distal lipoatrophy, visceral fat gain, myopathy, and vitiligo.

Lipedema

Lipedema (lipoedema), first described by Allen and Hines in 1940, is a painful, symmetric, disproportionate fat accumulation in the extremities of women, distinct from obesity and lymphedema, treated with compression and liposuction.

Oct 20, 2026

Lipegfilgrastim

Lipegfilgrastim (Lonquex) is a long-acting pegylated filgrastim (G-CSF) from Teva, EMA-approved 25 July 2013, given as one 6 mg subcutaneous dose per chemotherapy cycle to reduce neutropenia and febrile neutropenia in patients aged 2 years and older.

Lipid Accumulation Product

Lipid Accumulation Product (LAP), an index by Kahn (2005), estimates lipid overaccumulation as (waist circumference − 65 or 58 cm) × triglycerides; used to screen metabolic syndrome and predict mortality in diabetes.

Lipid emulsion therapy

Lipid emulsion therapy is the intravenous administration of a concentrated fat emulsion, usually soybean oil, to reverse local anesthetic systemic toxicity and other lipophilic drug poisoning.

Lipid nanocapsules

Lipid nanocapsules are biomimetic drug-delivery nanoparticles, 20 to 100 nm in diameter, with a liquid oily core of medium-chain triglycerides and a shell of PEGylated nonionic surfactant and lecithin, made by a solvent-free phase inversion process.

Lipid nanoparticle

A lipid nanoparticle (LNP) is a nanoscale vehicle that ferries RNA such as mRNA or siRNA into cells, the delivery system behind mRNA COVID-19 vaccines and the first approved siRNA drug.

Lipid nanoparticle organ tropism

Lipid nanoparticle organ tropism is the tendency of lipid nanoparticles to deliver nucleic acid cargo preferentially to one organ, usually the liver, depending on lipid composition.

Lipid nanoparticle siRNA delivery

Lipid nanoparticle siRNA delivery encapsulates small interfering RNA in nanoscale lipid particles that carry it into cells, and produced the first FDA-approved siRNA drug, patisiran, in 2018.

Lipid profile

Lipid profile (lipid panel): blood test measuring total cholesterol, HDL-C, and triglycerides, with calculated LDL-C and non-HDL-C, used for ASCVD risk screening; non-fasting sampling is now standard, with Martin/Hopkins or Sampson equations preferred over Friedewald.

Lipid–calcium–phosphate nanoparticles

Lipid–calcium–phosphate (LCP) nanoparticles are core–shell drug delivery particles with a calcium phosphate core wrapped in a lipid shell, developed in Leaf Huang's laboratory as an improvement on the earlier LPD formulation.

Lipinski's rule of five

Lipinski's rule of five (Ro5) is a medicinal chemistry guideline for oral drug-likeness: MW ≤500 Da, clogP <5, ≤5 H-bond donors, ≤10 acceptors, from Lipinski et al. 1997; extended by Veber and Ghose rules and challenged by beyond-Ro5 drugs.

Lipoabdominoplasty

Lipoabdominoplasty is a body-contouring operation combining liposuction with abdominoplasty, introduced by Saldanha in 2001; selective undermining preserves blood and lymphatic vessels, giving fewer complications than conventional abdominoplasty.

Lipoatrophy or lipodystrophy

Lipoatrophy or lipodystrophy is a term for rare disorders in which the body loses, or fails to develop, adipose tissue, leading to insulin resistance and diabetes.

Lipoblastoma

Lipoblastoma, also called lipoblastomatosis in its diffuse form, is a rare benign pediatric soft tissue tumor of fetal fat with PLAG1 (8q11-q13) rearrangements, treated by complete excision with about 17% pooled recurrence.

Lipocalin-2

Lipocalin-2, also known as neutrophil gelatinase-associated lipocalin (NGAL), is a protein of innate immunity and one of the earliest biomarkers of acute kidney injury, rising within 2–4 hours.

Lipodermatosclerosis

Lipodermatosclerosis, also called sclerosing panniculitis or hypodermitis sclerodermaformis, is a chronic inflammatory leg condition with subcutaneous fibrosis and skin hardening caused by venous insufficiency, featuring acute cellulitis-like and chronic inverted champagne bottle phases.

Lipodystrophy

Lipodystrophy: rare disorders of selective body-fat loss, genetic (CGL, FPLD; AGPAT2, BSCL2, LMNA genes) or acquired (AGL, APL, HIV-related), causing insulin resistance, diabetes, hypertriglyceridemia; treated with diet, metreleptin, statins.

Lipoid pneumonitis

Lipoid pneumonitis (lipoid pneumonia): rare lung inflammation from lipid buildup in alveoli; exogenous form from aspirated or inhaled oils (mineral oil, vaping products), endogenous (cholesterol) form from airway obstruction; diagnosed by fat attenuation on CT.

Lipoid proteinosis

Lipoid proteinosis (Urbach-Wiethe disease, hyalinosis cutis et mucosae) is a rare autosomal recessive genodermatosis from ECM1 mutations, causing hoarse cry from infancy, beaded eyelid papules, waxy scarring skin, and amygdala calcifications.

Lipoma

Lipoma: a common benign tumor of mature fat cells forming a soft, movable subcutaneous lump, usually in adults 40-60; painless and rarely treated, distinguished from liposarcoma by slow growth.

Lipoprotein insulin resistance index

The lipoprotein insulin resistance (LP-IR or LPIR) index is a blood test score, from 0 to 100, that estimates insulin resistance from six NMR-measured lipoprotein parameters.

Liposarcoma

Liposarcoma, a malignant soft tissue sarcoma of fat cells in adults, includes well-differentiated, dedifferentiated, myxoid, and pleomorphic subtypes with MDM2/CDK4 12q amplification and highly subtype-dependent survival.

Liposome

Liposome: spherical phospholipid bilayer vesicle with aqueous core, discovered by Bangham in 1965; sizes 20 nm–2.5 μm; drug nanocarrier behind Doxil and AmBisome, FDA-regulated as complex products.

Liposuction

Liposuction (suction lipectomy, tumescent liposuction) is a surgical body-contouring procedure that removes subcutaneous fat through a cannula; developed from the 1970s Fischer and Illouz work and Klein's 1985 tumescent technique, with about 12% minor complication rate and 317,196 US procedures in 2025.