This list includes 33 Diseases that start with L, from “Labyrinthitis” to “Lynch Syndrome”. Many entries are infections, genetic syndromes, and autoimmune conditions, reflecting a wide clinical range and practical relevance for quick lookups.
Diseases that start with L are a varied group of human conditions whose names begin with the letter L. Notable examples include Lyme disease, named after Lyme, Connecticut, and Lynch syndrome, a hereditary cancer predisposition.
Below you’ll find the table with Name, Symptoms, Causes and Treatments.
Name: You see the standard disease name and common synonyms so you can find the condition quickly and accurately.
Symptoms: You get 2–4 key signs to help recognize typical presentations and decide if you need more detail.
Causes: You find the primary cause and main risk factors in one concise line to understand likely origins.
Treatments: You see common first-line treatments and typical referral suggestions so you know how the condition is usually managed.
Diseases that start with L
| Name | ICD-10/ICD-11 code(s) | Key symptoms | Primary causes & risk factors |
|---|---|---|---|
| Labyrinthitis | H83.0 | Dizziness, vertigo, hearing loss, nausea | Viral or bacterial inner ear infection, respiratory illness |
| Lactose Intolerance | E73 | Bloating, gas, diarrhea after consuming dairy | Lactase enzyme deficiency, genetics, aging |
| Lambert-Eaton Myasthenic Syndrome | G73.1; C80.1 | Muscle weakness in limbs, trouble walking, droopy eyelids | Autoimmune response, often linked to small cell lung cancer |
| Laryngeal Cancer | C32 | Hoarse voice, persistent cough, sore throat, difficulty swallowing | Smoking, excessive alcohol use, HPV infection, age |
| Laryngitis | J04.0 | Hoarse or lost voice, sore throat, dry cough | Viral infections (common cold), overuse of voice, irritants |
| Laryngomalacia | Q31.5 | Noisy breathing (stridor), feeding difficulties, poor weight gain | Congenital soft tissues above the voice box, unknown cause |
| Lead Poisoning | T56.0 | Developmental delays, learning difficulties, irritability, abdominal pain | Ingesting or inhaling lead from paint, dust, water, or soil |
| Legg-Calvé-Perthes Disease | M91.1 | Limping, hip or groin pain, limited hip motion | Interrupted blood supply to the femoral head, cause unknown |
| Legionnaires’ Disease | A48.1 | Cough, fever, shortness of breath, muscle aches | Inhaling water droplets with Legionella bacteria |
| Leishmaniasis | B55 | Skin sores, fever, weight loss, enlarged spleen and liver | Protozoan parasite from infected sand fly bites |
| Lennox-Gastaut Syndrome | G40.4 | Multiple types of seizures, developmental delay, learning problems | Brain damage or malformation, genetic mutations, unknown causes |
| Leprosy | A30 | Discolored skin patches, skin growths, nerve damage, muscle weakness | Infection with Mycobacterium leprae bacteria |
| Leptospirosis | A27 | High fever, headache, muscle aches, jaundice | Contact with water or soil contaminated by infected animal urine |
| Leukemia | C91-C95 | Fatigue, frequent infections, easy bruising, unexplained weight loss | Abnormal white blood cell production, genetic factors, radiation |
| Leukoplakia | K13.2 | Thick, white patches inside the mouth or on the gums | Chronic irritation from tobacco, alcohol use, rough teeth |
| Lewy Body Dementia | G31.83 | Cognitive decline, visual hallucinations, movement problems like Parkinson’s | Abnormal protein deposits (Lewy bodies) in the brain |
| Lichen Planus | L43 | Itchy, flat-topped, purplish bumps on skin or lacy white patches in mouth | Autoimmune response, viral infections (Hepatitis C), medications |
| Lichen Sclerosus | L90.0 | White, patchy skin that is thinner than normal, itching, pain | Autoimmune condition, hormonal imbalances, genetics |
| Limb-Girdle Muscular Dystrophy | G71.0 | Progressive weakness in hip and shoulder muscles | Genetic mutations affecting muscle proteins |
| Lipoma | D17 | Soft, rubbery lump under the skin, usually painless | Unknown, tends to run in families |
| Liposarcoma | C49 | Growing lump under the skin, pain, swelling | Genetic mutations, unknown causes |
| Lissencephaly | Q04.3 | Severe developmental delay, seizures, feeding difficulties | Genetic mutations affecting fetal brain development |
| Listeriosis | A32 | Fever, muscle aches, nausea, diarrhea | Eating food contaminated with Listeria monocytogenes bacteria |
| Liver Cancer | C22.0 | Abdominal pain, yellowing of skin (jaundice), unexplained weight loss | Chronic hepatitis B or C infection, cirrhosis, heavy alcohol use |
| Loiasis | B74.3 | Eye worm, localized swelling (Calabar swellings), itching | Infection with Loa loa worm from deerfly bites |
| Locked-in Syndrome | G93.81 | Complete paralysis except for eye movements, full consciousness | Damage to the brainstem, often from a stroke or injury |
| Lung Cancer | C34 | Persistent cough, chest pain, shortness of breath, coughing up blood | Smoking, secondhand smoke, radon gas, asbestos exposure |
| Lupus | M32 | Butterfly-shaped face rash, fatigue, joint pain, fever | Autoimmune disease, genetics, environmental triggers |
| Lyme Disease | A69.2 | Bull’s-eye rash, fever, fatigue, joint pain | Bacterial infection from infected blacklegged tick bites |
| Lymphedema | I89.0 | Swelling in an arm or leg, feeling of heaviness or tightness | Damage to or removal of lymph nodes, often after cancer treatment |
| Lymphangitis | L03 | Red streaks on skin, fever, swollen lymph nodes, pain | Bacterial infection entering a cut or wound |
| Lymphoma | C81-C86 | Painless swelling of lymph nodes, fatigue, fever, night sweats | Mutations in lymphocytes (white blood cells), immune system issues |
| Lynch Syndrome | Z15.04; Z84.81 | N/A (risk factor) | Inherited genetic mutation |
Descriptions
Labyrinthitis
Inflammation of the inner ear, affecting balance and hearing. Most people recover fully, but severe cases may cause permanent hearing loss. See a doctor for vertigo.
Lactose Intolerance
A common digestive issue where the body can’t digest lactose, a sugar in milk. Managed by avoiding dairy or taking enzyme supplements.
Lambert-Eaton Myasthenic Syndrome
A rare autoimmune disorder that disrupts nerve-to-muscle communication, causing weakness. It’s strongly associated with certain cancers and requires specialist care.
Laryngeal Cancer
Cancer that forms in the tissues of the larynx (voice box). Early detection greatly improves the outcome. See a doctor for persistent hoarseness.
Laryngitis
Inflammation of the voice box (larynx), usually from a virus or strain. It’s typically temporary and resolves on its own with voice rest and hydration.
Laryngomalacia
A common congenital condition causing soft laryngeal tissues to flop into the airway when breathing. Most infants outgrow it, but severe cases may need surgery.
Lead Poisoning
A serious condition caused by lead buildup in the body. It is especially dangerous for children and can cause permanent neurological damage.
Legg-Calvé-Perthes Disease
A childhood hip disorder where blood supply to the top of the thigh bone is disrupted, causing the bone to die. Early treatment aims to keep the bone round.
Legionnaires’ Disease
A severe form of pneumonia caused by bacteria often found in water systems of large buildings. It requires prompt treatment with antibiotics and can be fatal.
Leishmaniasis
A parasitic disease spread by the bite of infected sand flies, found in parts of the tropics and subtropics. It ranges from skin sores to a severe systemic illness.
Lennox-Gastaut Syndrome
A severe form of childhood-onset epilepsy characterized by multiple types of seizures. It is difficult to treat and often persists into adulthood.
Leprosy
A chronic infectious disease, also known as Hansen’s disease, that primarily affects the skin, nerves, and eyes. It is curable with multidrug therapy.
Leptospirosis
A bacterial disease that affects humans and animals. It can cause a wide range of symptoms, and some infections can be life-threatening if not treated.
Leukemia
A group of cancers of the blood-forming tissues, including the bone marrow. Treatment depends on the type and stage but often includes chemotherapy.
Leukoplakia
A condition involving white patches on the mucous membranes of the mouth. Most are benign, but some show early signs of cancer, so a biopsy is often recommended.
Lewy Body Dementia
A progressive type of dementia that affects thinking, movement, behavior, and mood. It is the third most common cause of dementia after Alzheimer’s and vascular dementia.
Lichen Planus
An inflammatory condition that can affect the skin, hair, nails, and mucous membranes. It is not contagious but can be uncomfortable; treatment aims to relieve symptoms.
Lichen Sclerosus
A chronic inflammatory skin condition that primarily affects the genital and anal areas. It causes itching and pain and can lead to scarring if left untreated.
Limb-Girdle Muscular Dystrophy
A group of inherited diseases that cause weakness and wasting of the muscles in the arms and legs. The severity and progression vary greatly depending on the specific type.
Lipoma
A benign (non-cancerous) tumor made of fat tissue. Lipomas are very common, feel soft to the touch, and are generally harmless unless they cause pain or grow large.
Liposarcoma
A rare type of cancer that arises in fat cells in deep soft tissue, such as that inside the thigh or abdomen. Treatment usually involves surgery, radiation, or chemotherapy.
Lissencephaly
A rare brain formation disorder characterized by the absence of normal folds (gyri) in the cerebral cortex, making the brain surface smooth. It causes severe neurological impairment.
Listeriosis
A serious infection usually caused by eating contaminated food. It is particularly dangerous for pregnant women, newborns, and adults with weakened immune systems.
Liver Cancer
Cancer that begins in the cells of the liver. The most common type is hepatocellular carcinoma. Early detection is critical, as it is often advanced when diagnosed.
Loiasis
A parasitic disease caused by the Loa loa worm, transmitted by deerfly bites in West and Central Africa. It is known for worms visibly migrating across the eye.
Locked-in Syndrome
A rare neurological disorder where a person is fully conscious and aware but cannot move or communicate verbally due to complete paralysis of nearly all voluntary muscles.
Lung Cancer
A cancer that begins in the lungs. It is the leading cause of cancer death worldwide, primarily due to cigarette smoking. Treatment varies by type and stage.
Lupus
A chronic autoimmune disease where the immune system attacks its own tissues. It can affect many body systems, including joints, skin, kidneys, and the brain.
Lyme Disease
An infectious disease caused by Borrelia bacteria. Early antibiotic treatment is crucial for a full recovery, but delayed diagnosis can lead to long-term complications.
Lymphedema
A condition of localized fluid retention and tissue swelling caused by a compromised lymphatic system. There is no cure, but it can be managed with therapy and compression.
Lymphangitis
Inflammation of the lymphatic vessels, often caused by a bacterial infection spreading from the skin. It can be serious and requires prompt antibiotic treatment.
Lymphoma
A cancer of the lymphatic system, a part of the body’s germ-fighting network. The main types are Hodgkin’s lymphoma and non-Hodgkin’s lymphoma.
Lynch Syndrome
An inherited disorder that increases the risk of many types of cancer, particularly colorectal cancer. Genetic counseling and regular cancer screening are crucial for management.