8,704 articles
Allergic contact dermatitis due to topical medicaments
Allergic contact dermatitis due to topical medicaments (medicament contact allergy) is type IV hypersensitivity to topical antibiotic, corticosteroid, anesthetic, or vehicle ingredients, led by bacitracin and neomycin, diagnosed by patch testing.
Allergic contact urticaria
Allergic (immunologic) contact urticaria, ICD-11 EK10, is an IgE-mediated immediate wheal-and-flare reaction after skin contact with proteins or haptens such as latex and foods, potentially spreading to anaphylaxis; diagnosed by prick testing and specific IgE, treated by avoidance.
Allergic gingivitis
Allergic gingivitis (アレルギー性歯肉炎), ICD-11 DA0B.0, is gum inflammation from hypersensitivity to dental materials, toothpaste flavorings, or foods; diagnosed by patch testing and confirmed by resolution after allergen removal.
Allergic rhinitis
Allergic rhinitis (hay fever) is an IgE-mediated nasal inflammation from inhaled allergens, affecting about 400 million people, often with asthma; treated with intranasal corticosteroids, antihistamines, saline, and allergen immunotherapy.
Allergic rhinitis due to pollen
Allergic rhinitis due to pollen, or hay fever, is an IgE-mediated seasonal nasal allergy to tree, grass, and ragweed pollen. Distinguished from perennial rhinitis by seasonality; treated with intranasal corticosteroids, antihistamines, and immunotherapy.
Allergy
Allergy: immunologically initiated hypersensitivity, mainly IgE-mediated type I reactions. Covers Gell–Coombs types, mast-cell degranulation, allergens, diagnosis, immunotherapy, and omalizumab's 2024 approval for food allergy.
Allergy to cats
Allergy to cats, or cat dander allergy, is an IgE-mediated reaction mainly to the Fel d 1 protein from cat saliva and skin glands; managed by avoidance, HEPA filtration, medications, and allergen immunotherapy.
Allodynia
Allodynia, also called touch-evoked pain, is pain from a stimulus that does not normally provoke pain, defined by the IASP. Distinct from hyperalgesia, it arises through peripheral and central sensitization in neuropathic pain, fibromyalgia, and migraine.
Alloimmune haemolytic anaemia
Alloimmune hemolytic anemia is anemia caused by antibodies from another individual destroying red blood cells, arising most often through transfusion, pregnancy, or transplantation, and including disease of the fetus and newborn.
Alloimmune thrombocytopenia
Alloimmune thrombocytopenia, chiefly fetal and neonatal alloimmune thrombocytopenia (FNAIT, NAIT), is maternal anti-HPA antibody-mediated fetal platelet destruction, causing thrombocytopenia and intracranial hemorrhage; treated with IVIG and platelet transfusion.
Alopecia areata
Alopecia areata is an autoimmune, T-cell–mediated disease attacking hair follicles, causing nonscarring patchy hair loss, alopecia totalis, or universalis; treated with corticosteroids and FDA-approved JAK inhibitors baricitinib, ritlecitinib, and deuruxolitinib.
Alopecia totalis
Alopecia totalis is complete scalp hair loss from the autoimmune disease alopecia areata, non-scarring, often progressing within 6 months, with no FDA-approved therapy and limited treatment evidence including JAK inhibitors.
Alopecia universalis
Alopecia universalis (AU), the most severe form of alopecia areata, is complete autoimmune loss of all scalp and body hair, affecting about 0.03% of people; treated with JAK inhibitors or contact immunotherapy.
Alopecia-intellectual disability syndrome
Alopecia-intellectual disability syndrome, also called APMR or Perniola-Krajewska-Carnevale syndrome, is an extremely rare autosomal recessive genetic disorder combining hair loss with intellectual disability, described in fewer than 20 families worldwide.
Alpha-1 antitrypsin deficiency
Alpha-1 antitrypsin deficiency (AATD, Alpha-1, PiZZ) is a SERPINA1 inherited disorder causing early emphysema and liver disease; treated with IV augmentation therapy, with base-editing medicines like BEAM-302 in trials.
Alpha-dystroglycan-related limb-girdle muscular dystrophy R16
LGMD R16 (formerly LGMD2P, MDDGC9) is a rare autosomal recessive limb-girdle muscular dystrophy caused by DAG1 mutations, with childhood-onset proximal weakness, intellectual disability, microcephaly, and calf hypertrophy.
Alpha-gal syndrome
Alpha-gal syndrome (AGS), also called red meat allergy or mammalian meat allergy, is a tick-bite-induced IgE allergy to the sugar galactose-α-1,3-galactose, causing delayed reactions to mammalian meat, dairy, gelatin, and drugs like cetuximab; primarily linked to the lone star tick in the US.
Alpha-mannosidosis
Alpha-mannosidosis (lysosomal alpha-D-mannosidase deficiency) is a rare autosomal recessive lysosomal storage disorder caused by MAN2B1 mutations on chromosome 19, marked by immune deficiency, skeletal and facial abnormalities, hearing loss, and intellectual decline; treated with velmanase alfa ERT.
Alpha-N-acetylgalactosaminidase deficiency
Alpha-N-acetylgalactosaminidase deficiency, also known as Schindler disease or NAGA deficiency, is a very rare lysosomal storage disease first described in 1987, caused by deficient activity of the NAGA enzyme.
Alpha-thalassemia (α-thalassemia)
Alpha-thalassemia (α-thalassemia), also called alpha thalassemia, is an inherited anemia from HBA1/HBA2 alpha-globin gene deletions, ranging from silent carrier and trait to HbH disease and fatal Hb Bart hydrops fetalis; mitapivat approved 2025.
Alpha-thalassemia-intellectual disability syndrome linked to chromosome 16
ATR-16 syndrome (OMIM 141750), alpha-thalassemia-intellectual disability syndrome linked to chromosome 16, is a rare contiguous gene deletion of 16p13.3 removing HBA1/HBA2, causing alpha-thalassemia with variable intellectual disability, unlike X-linked ATR-X.
Alpha-thalassemia-myelodysplastic syndrome
Alpha-thalassemia-myelodysplastic syndrome (ATMDS, acquired hemoglobin H disease) is a rare acquired alpha-thalassemia caused by somatic ATRX mutations in myelodysplastic syndrome, affecting mainly older men, with about 80 cases reported.
Alport syndrome
Alport syndrome, a hereditary nephritis caused by COL4A3, COL4A4, or COL4A5 variants, causes hematuria, progressive kidney failure, hearing loss, and eye defects; treated with early RAS blockade, no FDA-approved drugs.
Alport syndrome-intellectual disability-midface hypoplasia-elliptocytosis syndrome
Alport syndrome-intellectual disability-midface hypoplasia-elliptocytosis syndrome, or AMME complex, is a rare X-linked contiguous gene deletion syndrome at Xq22.3 involving COL4A5, FACL4, and AMMECR1, affecting males with Alport syndrome, intellectual disability, midface hypoplasia, and elliptocytosis.
Alström syndrome
Alström syndrome is a rare autosomal recessive multisystem genetic disorder caused by ALMS1 variants, first described in 1959, causing blindness, hearing loss, obesity, diabetes, and heart failure.
Alteplase
Alteplase (Activase, Actilyse) is a recombinant tissue plasminogen activator thrombolytic for acute ischemic stroke, myocardial infarction, massive pulmonary embolism, and catheter occlusion; FDA approved 1987, 0.9 mg/kg stroke dosing, main risk bleeding.
Alternating skew deviation
Alternating skew deviation is a supranuclear vertical eye misalignment that reverses with gaze direction, affecting about 12% of skew deviation patients, usually from pretectal, cerebellar, or cervicomedullary lesions.
Aluminium bone disease
Aluminium bone disease (aluminium-related osteomalacia, dialysis-related adynamic bone) is defective bone mineralization from aluminium accumulation in dialysis and CKD patients, caused by aluminium hydroxide binders and contaminated dialysis water; diagnosed by bone biopsy or DFO test, treated with deferoxamine and aluminium withdrawal.
Aluminium excess
Aluminium excess (ICD-11 5B91.4), body aluminium overload causing bone disease, encephalopathy, and infant neurodevelopmental harm, mainly in kidney failure, dialysis, and parenteral nutrition patients.
Aluminium toxicity in people on dialysis
Aluminium toxicity in dialysis patients: accumulation from contaminated dialysate water and aluminium phosphate binders, causing dialysis dementia, osteomalacia, and microcytic anemia; prevented by reverse osmosis water and monitored via serum aluminium and DFO tests.