Acne
Blocked follicles, inflammation, and treatment options.
Health topics library
Conditions A–Z
A plain-language starting point for common diseases, disorders, and medical issues. Use these summaries to learn vocabulary and prepare questions—not to self-diagnose.
Allergies
Reactions to foods, medicines, pollen, and other triggers.
Alzheimer’s disease
Memory, thinking, behavior, caregiving, and support.
Anemia
Low red blood cells or hemoglobin and common causes.
Anxiety disorders
Persistent fear, worry, panic, and evidence-based care.
Arthritis
Joint pain, stiffness, inflammation, and function.
Asthma
Airway inflammation, triggers, inhalers, and action plans.
Atrial fibrillation
Irregular rhythm, stroke risk, symptoms, and treatment.
Back pain
Acute and chronic pain, red flags, and movement.
Cancer
Screening, diagnosis, staging, treatment, and support.
COPD
Chronic breathing limitation, smoking, and pulmonary care.
Coronary artery disease
Reduced blood flow to the heart and risk reduction.
Crohn’s disease
Inflammatory bowel disease affecting the digestive tract.
Depression
Mood, energy, thinking, treatment, and crisis support.
Diabetes
Glucose regulation, types, testing, management, and prevention.
Eczema
Itchy, inflamed skin and trigger management.
Endometriosis
Tissue-like growth, pelvic pain, fertility, and treatment.
Epilepsy
Seizures, diagnosis, safety, and medication management.
Fibromyalgia
Widespread pain, fatigue, sleep, and symptom management.
GERD
Acid reflux, heartburn, triggers, and treatment.
Heart failure
Reduced pumping or filling function and symptom monitoring.
High blood pressure
Blood pressure ranges, home monitoring, and risk reduction.
High cholesterol
Lipids, cardiovascular risk, lifestyle, and medications.
Hypothyroidism
Low thyroid hormone, symptoms, tests, and treatment.
Influenza
Flu symptoms, prevention, antivirals, and complications.
Kidney disease
Kidney function, testing, causes, and slowing progression.
Migraine
Headache attacks, triggers, prevention, and treatment.
Multiple sclerosis
Immune-related damage to the central nervous system.
Obesity
A complex chronic disease affecting health and wellbeing.
Osteoporosis
Low bone strength, fractures, screening, and prevention.
Parkinson’s disease
Movement, non-movement symptoms, therapy, and support.
Pneumonia
Lung infection, warning signs, treatment, and prevention.
Psoriasis
Immune-mediated skin plaques and systemic effects.
Rheumatoid arthritis
Autoimmune joint inflammation and disease-modifying care.
Sleep apnea
Repeated breathing interruptions and health effects.
Stroke
Brain blood-flow emergency, FAST signs, recovery, prevention.
Thyroid disease
Hormone imbalance, nodules, testing, and treatment.
Urinary tract infection
Bladder or kidney infection symptoms and treatment.
Ulcerative colitis
Inflammation and ulcers in the large intestine.
Viral hepatitis
Liver infection, testing, vaccines, and treatment.
Not finding a topic? Search the complete MedlinePlus A–Z index or ask a healthcare professional which type of specialist is appropriate.
How to use a condition page
Look for the full picture
A useful health guide should separate symptoms from diagnosis, explain testing, cover treatment choices and risks, and show when urgent care is needed.
1. Basics
What the condition is, who it affects, and how it develops.
2. Symptoms
Common patterns, variation, and red flags that need prompt care.
3. Diagnosis
History, examination, tests, and conditions that may look similar.
4. Options
Lifestyle, medicines, procedures, monitoring, and shared decisions.
MedlinePlus Health Topics
More than 1,000 regularly reviewed topics organized by body system, diagnosis, demographic group, and wellness area.
Visit official source ↗CDC Diseases & Conditions
Public-health information on infectious and chronic diseases, prevention, and outbreaks.
Visit official source ↗NIH Health Information
Health resources and research information from the National Institutes of Health.
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