Autoimmune & chronic conditions, explained

Hypothyroidism

Also: Underactive thyroid

The thyroid gland produces too little thyroid hormone, slowing metabolism, energy and temperature regulation.

Hashimoto's thyroiditis

Also: Chronic lymphocytic thyroiditis

An autoimmune condition where the immune system attacks the thyroid, usually leading to an underactive thyroid over time.

Type 2 diabetes

Also: T2D

A long-term condition where the body becomes resistant to insulin, leading to high blood sugar.

Type 1 diabetes

Also: T1D

An autoimmune condition where the immune system destroys insulin-producing cells, so the body can no longer regulate blood sugar.

Asthma

A common long-term condition where the airways are inflamed and sensitive, causing wheezing, breathlessness and coughing.

Migraine

A neurological condition causing intense, often one-sided headaches, sometimes with aura, nausea and sensitivity to light or sound.

Irritable bowel syndrome

Also: IBS

A common functional gut disorder causing abdominal pain, bloating and changes in bowel habit, without visible inflammation.

Osteoarthritis

Also: Wear-and-tear arthritis

The most common form of arthritis, where joint cartilage thins over time, causing pain, stiffness and reduced movement.

Hypertension

Also: High blood pressure

Persistently raised blood pressure that usually has no symptoms but increases risk of heart, kidney and stroke problems.

Eczema

Also: Atopic dermatitis

A common inflammatory skin condition causing dry, itchy, red patches, often linked with allergies and asthma.

Psoriasis & psoriatic arthritis

Also: Psoriatic disease

An autoimmune condition that speeds up skin cell turnover, causing scaly patches, and in some people affects the joints.

Rheumatoid arthritis

Also: RA

An autoimmune condition where the immune system attacks the joints, causing pain, swelling and stiffness, often in hands and feet.

Coeliac disease

Also: Celiac disease

An autoimmune reaction to gluten that damages the lining of the small intestine and affects nutrient absorption.

Endometriosis

A condition where tissue similar to the womb lining grows elsewhere, causing pain, heavy periods and sometimes fertility issues.

Polycystic ovary syndrome

Also: PCOS

A common hormonal condition affecting ovulation, often with irregular periods, excess androgens and polycystic ovaries.

Iron deficiency anaemia

A shortage of iron that reduces haemoglobin, causing tiredness, pale skin and shortness of breath.

Vitamin D deficiency

Low vitamin D levels, common in the UK, causing tiredness, bone and muscle pain and low mood.

Gout

A form of inflammatory arthritis caused by uric acid crystals in joints, causing sudden severe pain, often in the big toe.

Osteoporosis

Also: Bone thinning

A condition where bones become fragile and more likely to break, often silently until a fracture occurs.

Fibromyalgia

A long-term condition causing widespread pain, tiredness and sleep problems, linked to how the nervous system processes pain.

Chronic fatigue syndrome

Also: ME/CFS

A complex condition causing profound fatigue that does not improve with rest and worsens after activity.

Gastro-oesophageal reflux disease

Also: GERD, acid reflux

A common condition where stomach acid flows back into the oesophagus, causing heartburn and regurgitation.

Chronic sinusitis

Also: Chronic rhinosinusitis

Long-term inflammation of the sinuses causing a blocked nose, discharge and facial pressure for 12 weeks or more.

Allergic rhinitis

Also: Hay fever

An allergic reaction to pollen, dust mites or pet dander causing sneezing, a runny nose and itchy eyes.

Rosacea

A chronic facial skin condition causing redness, flushing and visible blood vessels, sometimes with acne-like bumps.

Hidradenitis suppurativa

Also: HS

A chronic inflammatory skin condition causing painful lumps and abscesses, usually in the armpits, groin and buttocks.

Alopecia areata

An autoimmune condition where the immune system attacks hair follicles, causing patchy hair loss.

Vitiligo

An autoimmune condition where the skin loses pigment in patches as pigment-producing cells are destroyed.

Lichen planus

An inflammatory condition causing itchy, flat, purple bumps on the skin or white lacy patches in the mouth.

Lichen sclerosus

A chronic skin condition causing thin, white, itchy patches, usually in the genital area.

Chronic urticaria

Also: Chronic hives

Recurrent itchy hives lasting more than six weeks, often driven by immune activation rather than allergy.

Sjögren's syndrome

Also: Sicca syndrome

An autoimmune condition that attacks moisture-producing glands, causing dry eyes and dry mouth.

Lupus (SLE)

Also: Systemic lupus erythematosus

A complex autoimmune condition that can affect skin, joints, kidneys and other organs, with flares and remissions.

Multiple sclerosis

Also: MS

An autoimmune condition where the immune system attacks the protective covering of nerves, disrupting nerve signals.

Inflammatory bowel disease

Also: IBD

Long-term autoimmune inflammation of the digestive tract — Crohn's disease and ulcerative colitis.

Crohn's disease

A type of IBD that can cause inflammation anywhere from mouth to anus, most often in the small intestine and colon.

Ulcerative colitis

Also: UC

A type of IBD causing inflammation and ulcers in the lining of the colon and rectum.

Ankylosing spondylitis

Also: Axial spondyloarthritis

An inflammatory arthritis mainly affecting the spine and sacroiliac joints, causing back pain and stiffness.

Psoriatic arthritis

Also: PsA

An inflammatory arthritis that affects some people with psoriasis, causing joint pain, swelling and stiffness.

Graves' disease

Also: Overactive thyroid

An autoimmune condition where the immune system stimulates the thyroid to make too much hormone.

Pernicious anaemia

Also: B12 deficiency anaemia

An autoimmune condition that stops the body absorbing vitamin B12, leading to anaemia and nerve symptoms.

Addison's disease

Also: Primary adrenal insufficiency

An autoimmune condition where the adrenal glands make too little cortisol and aldosterone.

Polymyalgia rheumatica

Also: PMR

An inflammatory condition causing aching and morning stiffness in the shoulders, neck and hips.

Giant cell arteritis

Also: Temporal arteritis

An inflammation of blood vessels, mainly in the head and neck, that can threaten sight and needs urgent treatment.

Raynaud's phenomenon

Also: Raynaud's

A condition where small blood vessels overreact to cold or stress, causing fingers and toes to turn white then blue then red.

Antiphospholipid syndrome

Also: APS, Hughes syndrome

An autoimmune clotting disorder where the immune system attacks certain fats, raising the risk of blood clots.

Scleroderma

Also: Systemic sclerosis

An autoimmune condition causing thickening of the skin and sometimes internal organs.

Dermatomyositis

An autoimmune condition causing muscle weakness and a distinctive skin rash.

Polymyositis

An autoimmune condition causing progressive muscle weakness, without the skin rash of dermatomyositis.

Vasculitis

A group of conditions where the immune system attacks blood vessels, causing inflammation that can affect any organ.

Behçet's disease

A rare inflammatory condition causing recurrent mouth and genital ulcers, eye inflammation and skin lesions.

Autoimmune hepatitis

Also: AIH

An autoimmune condition where the immune system attacks the liver, causing inflammation.

Primary biliary cholangitis

Also: PBC, primary biliary cirrhosis

An autoimmune condition that slowly damages the small bile ducts in the liver.

Primary sclerosing cholangitis

Also: PSC

An autoimmune condition causing inflammation and scarring of the bile ducts inside and outside the liver.

Autoimmune gastritis

Also: Autoimmune metaplastic atrophic gastritis

An autoimmune attack on the stomach lining that can reduce acid and intrinsic factor, leading to low B12.

Cushing's syndrome

Also: Hypercortisolism

A condition where the body has too much cortisol for a long time, causing weight, skin and mood changes.

Hypopituitarism

Also: Pituitary underactivity

A condition where the pituitary gland makes too little of one or more hormones, affecting many body systems.

Subacute thyroiditis

Also: De Quervain's thyroiditis

A temporary inflammation of the thyroid, often after a virus, causing a painful thyroid and temporary overactivity.

Postpartum thyroiditis

A temporary thyroid inflammation that can occur in the year after birth, swinging between over- and underactivity.

Thyroid eye disease

Also: Graves' ophthalmopathy

An autoimmune condition where muscles and tissue behind the eyes become inflamed, often with Graves' disease.

Type 1.5 diabetes

Also: LADA, latent autoimmune diabetes in adults

A slow-onset autoimmune diabetes in adults that shares features of type 1 and type 2.

Autoimmune polyglandular syndrome

Also: APS

A group of rare conditions where several endocrine glands are attacked by the immune system.

Myasthenia gravis

Also: MG

An autoimmune condition causing muscle weakness that worsens with activity and improves with rest.

Guillain-Barré syndrome

Also: GBS

A rare condition where the immune system attacks peripheral nerves, causing rapidly progressing weakness.

Chronic inflammatory demyelinating polyneuropathy

Also: CIDP

A chronic autoimmune nerve condition causing progressive weakness and sensory changes, related to Guillain-Barré.

Narcolepsy

A neurological sleep disorder causing excessive daytime sleepiness and sometimes sudden muscle weakness.

Neuromyelitis optica

Also: Devic's disease, NMO

A rare autoimmune condition attacking the optic nerves and spinal cord, causing vision and weakness symptoms.

Stiff person syndrome

Also: SPS, Moersch-Woltman syndrome

A rare autoimmune neurological condition causing severe muscle stiffness and spasms.

Autoimmune encephalitis

A group of conditions where the immune system attacks the brain, causing rapid psychiatric and neurological symptoms.

MOG antibody disease

Also: MOGAD

An autoimmune condition attacking myelin in the optic nerves and spinal cord, related to but distinct from MS and NMO.

Transverse myelitis

Inflammation of the spinal cord causing weakness, numbness and bladder or bowel changes, often on both sides.

Optic neuritis

Inflammation of the optic nerve causing eye pain and vision loss, sometimes the first sign of MS or MOGAD.

IgA nephropathy

Also: Berger's disease

A kidney condition where IgA builds up in the kidneys, causing inflammation and sometimes progressive damage.

Membranous nephropathy

A kidney condition where the immune system attacks the filtering units, causing protein leakage.

Lupus nephritis

Kidney inflammation caused by lupus, which can range from mild to severe.

Goodpasture's syndrome

Also: Anti-GBM disease

A rare autoimmune condition where antibodies attack the lungs and kidneys, causing bleeding and kidney failure.

IgA vasculitis

Also: Henoch-Schönlein purpura

A vasculitis that often follows infection, causing a rash, joint pain, belly pain and sometimes kidney issues.

Chronic kidney disease

Also: CKD

Long-term reduced kidney function, often from diabetes, high blood pressure or inflammatory kidney conditions.

Autoimmune haemolytic anaemia

Also: AIHA

A condition where the immune system destroys red blood cells faster than they are made, causing anaemia.

Immune thrombocytopenia

Also: ITP

An autoimmune condition where the immune system destroys platelets, causing bruising and bleeding.

Aplastic anaemia

A rare condition where the bone marrow stops making enough blood cells, often due to immune attack.

Paroxysmal nocturnal haemoglobinuria

Also: PNH

A rare acquired blood condition where red cells break down, causing anaemia, clots and dark urine.

Pemphigus

Also: Pemphigus vulgaris

A rare autoimmune skin disease causing severe blistering of the skin and mucous membranes.

Pemphigoid

Also: Bullous pemphigoid

An autoimmune blistering disease, more common in older adults, causing tense itchy blisters.

Dermatitis herpetiformis

Also: DH

An intensely itchy blistering skin rash linked to coeliac disease.

Linear IgA disease

Also: Linear IgA bullous dermatosis

A rare autoimmune blistering disorder with a distinct antibody pattern seen on skin biopsy.

Epidermolysis bullosa acquisita

Also: EBA

A rare autoimmune blistering disease causing fragile skin that blisters with minor trauma.

Eosinophilic oesophagitis

Also: EoE

A chronic allergic inflammatory condition of the oesophagus causing swallowing difficulty and food impaction.

Eosinophilic asthma

A type of severe asthma driven by high eosinophils, a type of white blood cell.

Mast cell activation syndrome

Also: MCAS

A condition where mast cells release too many inflammatory chemicals, causing allergic-type symptoms across body systems.

Histamine intolerance

A sensitivity to histamine-rich foods, causing symptoms that mimic allergy when breakdown is impaired.

Small intestinal bacterial overgrowth

Also: SIBO

An excess of bacteria in the small intestine causing bloating, gas and diarrhoea or constipation.

Interstitial cystitis

Also: Bladder pain syndrome

A chronic condition causing bladder pressure, pain and frequent urination without infection.

Chronic pelvic pain syndrome

Ongoing pain in the pelvic area without a clear infection, often linked with prostate, bladder or nerve sensitivity.

Adenomyosis

A condition where tissue similar to the womb lining grows into the muscle wall, causing painful, heavy periods.

Premature ovarian insufficiency

Also: POI, early menopause

Loss of ovarian function before age 40, causing irregular or stopped periods and low oestrogen.

Chronic obstructive pulmonary disease

Also: COPD

A long-term lung condition, usually from smoking, causing breathlessness, cough and wheeze.

Bronchiectasis

A long-term lung condition where airways are widened and scarred, causing mucus build-up and infections.

Interstitial lung disease

Also: ILD

A group of conditions causing inflammation and scarring of the lung tissue, leading to breathlessness.

Sarcoidosis

An inflammatory condition where tiny clumps of immune cells form in organs, most often lungs and lymph nodes.

Idiopathic pulmonary fibrosis

Also: IPF

A chronic scarring lung disease of unknown cause that worsens over time.

Chronic pancreatitis

Long-term inflammation of the pancreas causing pain, digestive problems and reduced enzyme production.

Autoimmune pancreatitis

Also: AIP

A rare autoimmune inflammation of the pancreas that can mimic pancreatic cancer.

Non-alcoholic fatty liver disease

Also: MASLD, metabolic-associated steatotic liver disease

A buildup of fat in the liver not caused by alcohol, linked to weight, diabetes and metabolic health.

Long COVID

Also: Post-COVID condition

Ongoing symptoms after COVID-19, including fatigue, brain fog and breathlessness, lasting weeks to months.

Postural orthostatic tachycardia syndrome

Also: POTS

A condition where standing causes a large rise in heart rate, with dizziness, fatigue and brain fog.

Ehlers-Danlos syndrome (hypermobility)

Also: hEDS, joint hypermobility

A group of connective tissue disorders causing joint hypermobility, skin changes and sometimes pain or gut symptoms.

Osteopenia

Also: Low bone density

Lower-than-normal bone density that is not yet osteoporosis, identified on a bone density scan.

Reactive arthritis

Also: Reiter's syndrome

A form of arthritis that develops after an infection, often gut or urinary, causing joint pain and swelling.

Enteropathic arthritis

A form of inflammatory arthritis linked to inflammatory bowel disease, affecting joints and the spine.

Juvenile idiopathic arthritis

Also: JIA

A group of inflammatory arthritis conditions that begin before age 16, causing joint swelling and stiffness.

Discoid lupus

Also: Discoid lupus erythematosus

A chronic autoimmune skin condition causing scaly, disc-shaped patches, usually on sun-exposed skin.

Drug-induced lupus

A lupus-like condition triggered by certain medications, which usually resolves when the drug is stopped.

Mixed connective tissue disease

Also: MCTD

An overlap condition with features of lupus, scleroderma and polymyositis, linked to anti-U1 RNP antibodies.

Undifferentiated connective tissue disease

Also: UCTD

A condition with autoimmune features that do not yet fit a specific connective tissue disease.

Relapsing polychondritis

A rare autoimmune condition causing repeated inflammation of cartilage, especially ears, nose and airways.

Cogan's syndrome

A rare autoimmune condition causing eye inflammation and hearing loss, sometimes with blood vessel inflammation.

Susac's syndrome

A rare autoimmune condition affecting tiny blood vessels in the brain, retina and inner ear.

Hashimoto's encephalopathy

Also: Steroid-responsive encephalopathy

A rare brain condition linked to thyroid antibodies, causing confusion and seizures that often respond to steroids.

Rasmussen's encephalitis

A rare chronic brain inflammation, usually in children, causing seizures and loss of function on one side.

Autoimmune autonomic ganglionopathy

Also: AAG

A rare autoimmune condition attacking the autonomic nervous system, affecting blood pressure, heart rate and digestion.

Lambert-Eaton myasthenic syndrome

Also: LEMS

An autoimmune condition causing muscle weakness, often linked to an underlying tumour.

Isaacs' syndrome

Also: Neuromyotonia

A rare autoimmune nerve condition causing continuous muscle stiffness and twitching.

Morvan's syndrome

A rare autoimmune condition combining neuromyotonia with sleep, brain and autonomic symptoms.

Autoimmune retinopathy

A rare autoimmune condition where the immune system attacks the retina, causing vision loss.

Autoimmune optic neuropathy

An autoimmune attack on the optic nerve causing vision loss, distinct from optic neuritis of MS.

Chronic relapsing inflammatory optic neuropathy

Also: CRION

A relapsing autoimmune optic nerve condition causing repeated vision loss, often steroid-responsive.

Vogt-Koyanagi-Harada disease

Also: VKH disease

A rare autoimmune condition affecting the eyes, ears, skin and brain, causing vision and hearing symptoms.

Sympathetic ophthalmia

A rare autoimmune eye condition where injury to one eye triggers inflammation in the other.

Autoimmune inner ear disease

Also: AIED

A rare autoimmune condition causing progressive hearing loss, sometimes with dizziness.

IgG4-related disease

Also: IgG4-RD

A rare immune condition causing lumps and tissue thickening in organs such as pancreas, bile ducts and kidneys.

Alopecia totalis

An autoimmune condition causing total loss of hair on the scalp.

Alopecia universalis

An autoimmune condition causing loss of all body and scalp hair.

Pemphigus foliaceus

A milder autoimmune blistering disease affecting the top layer of skin, causing scaly crusts.