This list includes 30 Diseases that start with I, from “Ichthyosis vulgaris” to “Ischemic stroke”. It is useful for quick reference, study, and initial clinical lookup. The list features genetic, infectious, vascular and inflammatory diseases commonly seen in practice.
Diseases that start with I are medical conditions whose standardized names begin with the letter I. Notable examples include “Ischemic stroke,” a major global cause of disability and death.
Below you’ll find the table with Disease, Symptoms, Causes and Treatments.
Disease: Contains the standardized disease name you can use for further lookup or citation.
Symptoms: Lists the 2–4 key symptoms to help you recognize common presentations quickly.
Causes: Summarizes the primary cause and main risk factors or pathophysiology in one concise line.
Treatments: Notes first-line or typical treatment options and when to seek specialist referral.
Diseases that start with I
| Name | ICD-10/ICD-11 code(s) | Key symptoms | Causes & main treatments |
|---|---|---|---|
| Influenza | J09-J11 | fever, cough, sore throat | influenza virus; antivirals, rest, fluids |
| Iron deficiency anemia | D50 | fatigue, pallor, shortness of breath | low iron (blood loss, poor diet); iron supplements, investigate cause |
| Ischemic heart disease | I20-I25 | chest pain, shortness of breath, fatigue | atherosclerosis; medications, PCI/CABG referral |
| Ischemic stroke | I63 | sudden weakness, speech difficulty, vision loss | blood vessel blockage; urgent thrombolysis, stroke unit care |
| Impetigo | L01 | honey-crust skin lesions, itching, redness | bacterial (Staph/Strep); topical/oral antibiotics |
| Infective endocarditis | I33 | fever, new heart murmur, fatigue | bacterial/fungal heart valve infection; IV antibiotics, cardiology care |
| Irritable bowel syndrome | K58 | abdominal pain, bloating, diarrhea/constipation | gut‑brain interaction, stress; diet, fiber, meds, CBT referral |
| Inflammatory bowel disease | K50-K51 | abdominal pain, diarrhea, weight loss | immune-mediated gut inflammation; steroids, biologics, GI referral |
| Infectious mononucleosis | B27 | fever, sore throat, swollen lymph nodes | Epstein–Barr virus; rest, fluids, avoid contact sports |
| Insomnia | G47.0 | difficulty falling asleep, daytime tiredness | stress, mental/medical causes; sleep hygiene, CBT, short-term meds |
| Intussusception | K56.1 | intermittent abdominal pain, vomiting, bloody stools | telescoping of intestine (children); ultrasound reduction, surgery |
| Intestinal obstruction | K56 | abdominal pain, vomiting, constipation | adhesions, hernia, tumor; decompression, surgery |
| Inclusion body myositis | — | slow muscle weakness, difficulty swallowing, falls | uncertain immune/degenerative; supportive care, neurology referral |
| Infantile spasms | — | sudden spasms, developmental regression, seizures | often structural/genetic; urgent neurology, ACTH or vigabatrin |
| Infant botulism | — | constipation, poor feeding, weak cry, floppy baby | Clostridium botulinum toxin ingestion; hospital care, human immunoglobulin |
| Invasive candidiasis | — | fever, organ dysfunction, sepsis signs | Candida bloodstream infection; IV antifungals, hospital care |
| Ichthyosis vulgaris | — | dry, scaly skin, itching | genetic skin barrier abnormality; emollients, dermatology care |
| Inclusion conjunctivitis | — | red eye, discharge, eyelid swelling | Chlamydia trachomatis infection; topical/oral antibiotics, ophthalmology |
| Inflammatory breast cancer | — | breast swelling, redness, rapid enlargement | aggressive breast cancer subtype; oncology referral, chemo/surgery |
| Ischemic colitis | K55 | abdominal pain, bloody diarrhea, tenderness | reduced intestinal blood flow; supportive care, vascular/surgical referral |
| Immune thrombocytopenia | D69.3 | easy bruising, bleeding, low platelets | autoimmune platelet destruction; steroids, hematology referral, IVIG |
| Idiopathic pulmonary fibrosis | J84.1 | progressive breathlessness, dry cough, fatigue | unknown; antifibrotics, pulmonology referral, oxygen |
| Ischemic optic neuropathy | H47.0 | sudden painless vision loss, visual field defect | vascular compromise to optic nerve; urgent ophthalmology, manage vascular risk |
| Iritis | H20 | eye pain, light sensitivity, blurred vision | autoimmune or infection; steroid eye drops, ophthalmology |
| Idiopathic intracranial hypertension | G93.2 | headache, visual disturbances, papilledema | unknown (obesity risk); weight loss, acetazolamide, neurology |
| Iliotibial band syndrome | — | lateral knee pain, tenderness with activity | overuse (runners); physical therapy, activity modification |
| Infantile hemangioma | — | red raised skin lesion, growth phase, involution later | benign vascular tumor; observation, propranolol, dermatology |
| Inhalation anthrax | A22 | fever, severe respiratory distress, mediastinal widening | Bacillus anthracis inhalation; urgent antibiotics, antitoxin, critical care |
| Infective keratitis | — | eye pain, redness, reduced vision | bacterial/fungal viral infection; topical antimicrobials, ophthalmology |
| Inflammatory myopathy | M33,M60 | muscle weakness, fatigue, elevated CK | immune-mediated muscle inflammation; steroids, immunosuppressants, rheumatology |
Descriptions
Influenza
Seasonal viral respiratory infection causing fever, aches and cough. Affects all ages, usually self-limited but can cause severe illness in older adults and young children.
Iron deficiency anemia
Common anemia that causes tiredness and breathlessness; more frequent in women, children and people with chronic blood loss.
Ischemic heart disease
Reduced blood flow to the heart causing angina or heart attacks, common in middle-aged and older adults.
Ischemic stroke
Brain injury from blocked artery. Rapid treatment improves outcomes; often causes lasting disability.
Impetigo
Contagious superficial skin infection, especially in children, usually treated with antibiotics.
Infective endocarditis
Infection of heart valves requiring prolonged treatment; risk in people with valve disease or IV drug use.
Irritable bowel syndrome
Chronic functional gut disorder with variable bowel habits; symptoms may flare with stress or foods.
Inflammatory bowel disease
Includes Crohn’s disease and ulcerative colitis, chronic relapsing conditions causing intestinal inflammation.
Infectious mononucleosis
Viral illness common in teens and young adults causing prolonged fatigue and sore throat.
Insomnia
Persistent trouble sleeping that impairs daytime function; common and treatable with behavioral approaches.
Intussusception
Pediatric emergency causing bowel obstruction, most common in infants aged 6–36 months.
Intestinal obstruction
Blocked intestine needing urgent care; can be partial or complete and may require surgery.
Inclusion body myositis
Progressive inflammatory muscle disease of older adults causing gradual weakness and disability.
Infantile spasms
Severe early-life epilepsy syndrome requiring prompt treatment to reduce developmental harm.
Infant botulism
Rare infant illness causing muscle weakness; requires urgent supportive care.
Invasive candidiasis
Serious systemic yeast infection in hospitalized or immunocompromised patients.
Ichthyosis vulgaris
Common inherited skin condition causing dry, flaky skin from childhood onward.
Inclusion conjunctivitis
Conjunctivitis caused by chlamydia, more common in newborns and sexually active adults.
Inflammatory breast cancer
Rare, rapid-onset breast cancer presenting like infection, needs urgent cancer treatment.
Ischemic colitis
Colon injury from poor blood flow, often in older adults with vascular disease.
Immune thrombocytopenia
Autoimmune low platelet disorder causing bleeding risk, variable course from acute to chronic.
Idiopathic pulmonary fibrosis
Progressive scarring of lungs in older adults, leads to breathlessness and reduced quality of life.
Ischemic optic neuropathy
Sudden loss of vision from reduced blood flow to the optic nerve, often in older adults.
Iritis
Inflammation of the iris causing pain and photophobia; treatable but can recur.
Idiopathic intracranial hypertension
Raised brain pressure without tumor, causes headaches and vision changes, often in young obese women.
Iliotibial band syndrome
Common cause of outer knee pain from friction of the iliotibial band in athletes.
Infantile hemangioma
Common benign blood-vessel tumor in infants; many regress spontaneously or respond to treatment.
Inhalation anthrax
Rare but severe form of anthrax causing life-threatening respiratory illness after spore inhalation.
Infective keratitis
Corneal infection that can threaten sight; urgent eye care improves outcomes.
Inflammatory myopathy
Group of autoimmune muscle diseases causing progressive weakness and slowed physical function.