Allergic granulomatosis also known as Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss Syndro...

Allergic granulomatosis and angiitis or Eosinophilic granulomatosis with polyangiitis is a condition that affects the sm...

Chikungunya is a rare viral infection transmitted by the bite of an infected mosquito. It is characterized by a rash, fever, and severe joint pain (arthralgias) that usually lasts for three to seven days. Because of its effect on the joints, Chiku...

Atopic dermatitis facts Atopic dermatitis is a type of eczema. The disease may be inherited and genetically determined. The patient's skin may be "super sensitive" to many irritants. Dry, scaly patches ...

Bloom syndrome is a rare genetic disorder characterized by short stature; increased sensitivity to light (photosensitivity); multiple small dilated blood vessels on the face (facial telangiectasia), often resembling a butterfly in shape; immune de...

Bloom syndrome is a rare genetic disorder characterized by short stature; increased sensitivity to light (photosensitivity); multiple small dilated blood vessels on the face (facial telangiectasia), often resembling a butterfly in shape; immune de...

General DiscussionChagas Disease is a tropical infectious disease caused by the parasite Trypanosoma cruzi. It is transmitted by the bite of one of several species of blood-sucking insects or by blood transfusion. Acute Chagas Disease usu...

Dengue Fever is an acute viral infection characterized by fever. It is caused by a bite from mosquitoes carrying dengue virus. The primary form of Dengue Fever is characterized by a skin rash and a high fever with severe pain in the head and muscl...

Bullous pemphigoid is an uncommon skin disease characterized by tense blisters on the surface of the skin. Occasionally, the inner lining tissue of the mouth, nasal passages, or conjunctivae of the eyes (mucous membrane tissue) can be involved. Th...

Biotinidase deficiency (BTD) is a treatable, metabolic disorder that is the result of a low concentration, or complete lack, of the enzyme, biotinidase. Biotinidase deficiency is an inherited disorder in which the body is not able to properly proc...

Chickenpox (varicella) is a viral infection that causes an itchy rash with small, fluid-filled blisters. Chickenpox is highly contagious to people who haven't had the disease or been vaccinated against it. Before routine chickenpox vaccination, vi...

Chickenpox, also known as varicella, is a highly contagious viral infection caused by the varicella-zoster virus. It is characterized by a red, itchy rash that usually starts on the face, chest, and back and then spreads to the rest of the body. O...

Chikungunya is a viral disease transmitted to humans by infected mosquitoes, specifically the Aedes aegypti and Aedes albopictus species. The most common symptoms of Chikungunya include fever, joint pain, headache, muscle pain, rash, and joint swe...

CHILD syndrome (an acronym for congenital hemidysplasia with ichthyosiform erythroderma and limb defects) is an inherited disorder, affecting primarily women, that is characterized by ichthyosis-like skin abnormalities and limb defects on one side...

An epidemic is defined as occurring when "new cases of a certain disease, in a given human population during a given time period, substantially exceed what is expected based upon recent experience." Pediatric obesity has reached epidemic proportio...

Collagenous colitis is a rare digestive disorder that primarily affects females and typically becomes apparent during middle age. The disorder is characterized by inflammatory changes of the mucous membranes (mucosa) of the colon (colitis) and abn...

Ulcerative colitis (UL-sur-uh-tiv koe-LIE-tis) is an inflammatory bowel disease ...

Ulcerative colitis (UL-sur-uh-tiv koe-LIE-tis) is an inflammatory bowel disease (IBD) that causes inflammation and ulcers (sores) in your digestive tract. Ulcerative colitis affects the innermost lining of your large intestine (colon) and rectum. ...

Mixed connective tissue disease facts Connective tissues are the framework of the cells of the body. Mixed connective tissue disease is an "overlap" combination of connective tissue diseases. Diagnosis of mixed c...

Contact dermatitis facts Contact dermatitis is a rash that occurs at the site of exposure to a substance capable of producing an allegic or irritant skin response. Contact dermatitis can be caused by noxious, irritating su...

Cryptococcus is a fungus that is found in soil all over the world, usually in association with bird droppings. Cryptococcus neoformans is the most common Cryptococcus species that causes illness in humans. Cryptococcus gattii, a less common specie...

Degos disease is a very rare disease in which small and medium-sized arteries become blocked, preventing proper blood flow to the affected areas. You may also develop skin lesions, which can last from weeks to years depending on the extent of the ...

Degos disease is an extremely rare disorder in which small and medium sized arteries become blocked (occlusive arteriopathy), restricting the flow of blood to affected areas. Degos disease usually causes characteristic skin lesions that may last f...

Dermatitis herpetiformis, also known as Duhring disease, is a rare, chronic, skin disorder characterized by the presence of groups of severely itchy (pruritic) blisters and raised skin lesions (papules). These are more common on the knees, elbows,...

Eczema facts Eczema is not a single disease but a reaction pattern of the skin produced by a number conditions. Atopic dermatitis, a common causes of eczema, is more prevalent in those with asthma and hay fever. ...

Tuberous sclerosis is a rare genetic multisystem disorder that is typically apparent shortly after birth. The disorder may be characterized by episodes of uncontrolled electrical activity in the brain (seizures); mental retardation; distinctive sk...

Erythema multiforme (EM) is the name applied to a group of hypersensitivity disorders, affecting mostly children and young adults, and characterized by symmetric red, patchy lesions, primarily on the arms and legs. The cause is unknown, but EM fre...

Erythropoietic protoporphyria (EPP) is a rare inherited metabolic disorder characterized by a deficiency of the enzyme ferrochelatase (FECH). Due to abnormally low levels of this enzyme, excessive amounts of protoporphyrin accumulate in the bone m...

Erythropoietic protoporphyria (EPP) is a rare inherited metabolic disorder characterized by a deficiency of the enzyme ferrochelatase (FECH). Due to abnormally low levels of this enzyme, excessive amounts of protoporphyrin accumulate in the bone m...

Extrinsic Allergic Pneumonia, also known as Allergic Interstitial Pneumonitis and Hypersensitivity Pneumonitis, is an inflammatory syndrome that affects the lungs. Extrinsic: the origin is an external matter - an antigen. Allergic: The cau...

Fabry disease is caused by the lack of or faulty enzyme needed to metabolize lipids, fat-like substances that include oils, waxes, and fatty acids. The enzyme is known as ceramide trihexosidase, also called alpha-galactosidase-A. A mutation in the...

Formaldehyde Poisoning is a disorder brought about by breathing the fumes of formaldehyde. This can occur while working directly with formaldehyde, or using equipment cleaned with formaldehyde. Major symptoms may include eye, nose, and throat irri...

Formaldehyde Poisoning is a disorder brought about by breathing the fumes of formaldehyde. This can occur while working directly with formaldehyde, or using equipment cleaned with formaldehyde. Major symptoms may include eye, nose, and throat irri...

Formaldehyde is a transitional molecule that participates in a wide range of biological activities. It can be found in a variety of everyday items, including meals. It's also used in medicine to treat a variety of ailments. Formalin is a 40 percen...

Fabry disease is a rare genetic disorder of fat (lipid) metabolism characterized by a deficiency of the enzyme alpha-galactosidase A (previously known as ceramide trihexosidase). The disorder belongs to a group of diseases known as lysosomal stora...

Grover's disease is a rare, transient skin disorder that consists of small, firm, raised red lesions, most often on the skin of the chest and back. Diagnosis of this disorder becomes apparent under microscopic examination when the loss of the "cem...

Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the w...

Hand, Foot, and Mouth Disease (HFMD) is a common viral illness that usually affects infants and children under the age of 5, although it can also occur in older children and adults. It is caused by several different viruses, most commonly the coxs...

Hartnup disease is a rare metabolic disorder inherited as an autosomal recessive trait. It involves an inborn error of amino acid metabolism as well as niacin deficiency. Factors that may precipitate acute attacks of this disorder may include poor...

Hartnup disease is a rare metabolic disorder inherited as an autosomal recessive trait. It involves an inborn error of amino acid metabolism as well as niacin deficiency. Factors that may precipitate acute attacks of this disorder may include poor...

Heat rash facts Heat rash occurs when the skin's sweat glands are blocked and the sweat produced cannot get to the surface of the skin to evaporate. This causes inflammation that results in a rash. Common symptoms of heat ...

Herpes Zoster, commonly known as shingles, is a viral infection caused by the varicella-zoster virus, the same virus that causes chickenpox. It is characterized by a painful rash with blisters that typically appears on one side of the face or body...

Kikuchi's disease, also known as histiocytic necrotizing lymphadenopathy, is a rare, benign, (noncancerous, nonmalignant) disorder of the lymph nodes of young adults, predominantly in young women. This disorder is often mistaken for malignant lymp...

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The l...

Histoplasmosis is an infection caused by the fungus Histoplasma. The fungus can be found in the environment, particularly in soil with a high concentration of bird or bat droppings. Histoplasma is mostly found in the central and eastern United Sta...

Papular urticaria, usually called hives, is characterized by large numbers of very itchy red bumps (papules) that come and go every few days over a period of a month or so. The bumps are usually between 0.2 and 2 cm. in size and some may develop i...

Biotinidase deficiency (BTD) is a treatable, metabolic disorder that is the result of a low concentration, or complete lack, of the enzyme, biotinidase. Biotinidase deficiency is an inherited disorder in which the body is not able to properly proc...

Cowpox is a viral disease that normally affects the udders and teats of cows. On rare occasions, it may be transmitted to humans and produce a characteristic red skin rash and abnormally enlarged lymph nodes (lymphadenopathy). Cowpox is caused by ...

Human Immunodeficiency Virus (HIV) is a virus that attacks the immune system, specifically targeting CD4 cells (T cells), which help the body fight off infections. If left untreated, HIV can lead to the disease known as Acquired Immunodeficiency S...

The WAS-related disorders are a spectrum of conditions affecting the immune system that are caused by mutations in the WAS gene. These disorders include Wiskott-Aldrich syndrome, X-linked thrombocytopenia and X-linked congenital neutropenia. The W...

Incontinentia Pigmenti (IP) is a rare genetic dermatological disorder affecting the skin, hair, teeth, and central nervous system. Progressive skin changes occur in four stages, the first of which appear in early infancy or can be present at birth...

Intertrigo is a dermatitis that only affects skin folds. Intertrigo is caused when skin is irritated by friction, which is enhanced by moisture and heat. Risk factors for intertrigo include obesity, heat, and humidity....

Jock itch facts Jock itch is a very common groin rash. Roughly half of jock itch is due to fungus. The remainder is caused by moisture, irritation, and bacterial overgrowth. Symptoms and signs of jock itch includ...

Jock itch, also known as tinea cruris, is a fungal infection that affects the skin of the groin area. It is caused by a type of fungus called dermatophytes, which thrive in warm, moist environments. Jock itch is characterized by red, itchy, and so...

Until recently the relationship of Stevens-Johnson syndrome to other severe blistering disorders was a matter of some debate. Now a consensus seems to be evolving that describes SJS as a rare disorder involving lesions of the mucous membranes alon...

Kikuchi's disease, also known as histiocytic necrotizing lymphadenopathy, is a rare, benign, (noncancerous, nonmalignant) disorder of the lymph nodes of young adults, predominantly in young women. This disorder is often mistaken for malignant lymp...

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The l...

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The l...

Latex allergy facts Latex allergy is dramatically on the rise throughout the world. Latex allergy rises with exposure and is suspected to continue to rise until a latex substitute is found. Latex allergy can be s...

Lichen planus facts Lichen planus is a chronic recurrent rash of unknown cause with no established cure. Lichen planus generally affects adults and can involve any portion of the body, but it has a predilection for the wri...

Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the w...

Congenital syphilis is a chronic infectious disease caused by a spirochete (treponema pallidum) acquired by the fetus in the uterus before birth. Symptoms of this disease may not become apparent until several weeks or months after birth and, in so...

Systemic lupus erythematosus (SLE) is an autoimmune disease. SLE is characterized by the production of unusual antibodies in the blood. SLE is eight times more common in women than men. The cause(s) of SLE is (ar...

Measles is a highly contagious viral infection that primarily affects children. It is characterized by a red, blotchy rash that typically starts on the face and spreads to the rest of the body. Other symptoms of measles include fever, cough, runny...

Meningococcal disease is a serious bacterial infection caused by the bacterium Neisseria meningitidis. It can lead to meningitis (inflammation of the membranes surrounding the brain and spinal cord) and septicemia (blood poisoning). Meningococcal ...

Mononucleosis, commonly known as mono, is a viral infection caused by the Epstein-Barr virus (EBV). It is most commonly seen in teenagers and young adults, but can affect people of any age. Mono is typically spread through saliva, which is why it ...

Marinesco-Sjogren syndrome (MSS) is a rare genetic disorder that affects multiple organ systems of the body. Common symptoms include difficulty coordinating voluntary movements due to degeneration (atrophy) of the cerebellum (cerebellar ataxia), c...

Mucha-Habermann disease, also known as pityriasis lichenoides et varioliformis acuta or PLEVA, is a rare skin disorder. The lesions most often appear on the trunk and the arms and legs. Lesions tend to develop in small groups. Mucha-Habermann dise...

Listeriosis is a rare but serious infectious disease caused by the bacterium Listeria monocytogenes, which is predominantly transmitted to humans through the consumption of contaminated food. Clinical syndromes associated with listeriosis include ...

General DiscussionNeonatal lupus is a rare autoimmune disorder that is present at birth (congenital). Affected infants often develop a characteristic red rash or skin eruption. In addition, infants with neonatal lupus may develop liver di...

Neonatal lupus is a rare autoimmune disorder that is present at birth (congenital). Affected infants often develop a characteristic red rash or skin eruption. In addition, infants with neonatal lupus may develop liver disease, a heart condition kn...

Henoch-Schonlein purpura is a rare inflammatory disease of the small blood vessels (capillaries) and is usually a self-limited disease. It is the most common form of childhood vascular inflammation (vasculitis) and results in inflammatory changes ...

Ocular rosacea is a type of rosacea that affects the eyes. It is characterized by redness, burning, stinging, and itching of the eyes, as well as dryness, sensitivity to light, and the formation of small cysts on the eyelids. In some cases, ocular...

Penile cancer is a disease in which malignant (cancer) cells form in the tissues of the penis. The penis is a rod-shaped male reproductive organ that passes sperm and urine from the body. It contains two types of erectile tissue (spongy ti...

Penile cancer is a disease in which malignant (cancer) cells form in the tissues of the penis. The penis is a rod-shaped male reproductive organ that passes sperm and urine from the body. It contains two types of erectile tissue (spongy ti...

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The l...

Ramsay Hunt syndrome (also termed Hunt's Syndrome and herpes zoster oticus) is a herpes zoster virus infection of the geniculate ganglion of the facial nerve. It is caused by reactivation of herpes zoster virus that has previously caused chickenpo...

Ramsay Hunt syndrome (RHS) is a rare neurological disorder characterized by paralysis of the facial nerve (facial palsy) and a rash affecting the ear or mouth. Ear abnormalities such as ringing in the ears (tinnitus) and hearing loss may also be p...

Ringworm, also known as tinea, is a common fungal infection of the skin that can affect different parts of the body, including the scalp, feet, groin, and nails. Despite its name, ringworm is not caused by a worm but by various types of fungi that...

Toxic epidermal necrolysis (TEN) is a rare, sometimes life-threatening unless properly treated, immunological disorder of the skin. It is characterized by blisters that meld into one another to cover a substantial portion of the body (30% and more...

Roseola facts Roseola is a mild illness caused by a virus infection most commonly involving, young children. A sudden high fever that lasts for three to five days is an early feature of roseola. Mild nasal congestion and l...

Rothmund-Thomson syndrome (RTS) is a rare genetic disorder that can affect many parts of the body. The disorder is characterized by distinctive abnormalities of the skin, sparse hair, eyelashes and/or eyebrows, small stature, skeletal and dental a...

Rothmund-Thomson syndrome is a rare condition that affects many parts of the body, particularly the skin....

Rubella, also known as German measles, is a contagious viral infection that causes a mild fever and a red rash on the skin. It is typically a mild illness, but can be more serious for pregnant women, as it can cause birth defects in the developing...

Scabies is an itchy, highly contagious skin disease caused by an infestation by the itch mite Sarcoptes scabiei. Direct skin-to-skin contact is the mode of transmission. A severe and relentless itch is the predominant symp...

Scabies is a highly contagious skin infestation caused by the microscopic mite Sarcoptes scabiei. It is characterized by intense itching and a pimple-like rash. Scabies is usually spread through close physical contact with an infected person, and ...

Shingles is a medical condition that is caused by the reactivation of the chickenpox-causing virus in the body. Shingles are extremely painful but it isn’t life-threatening.  Shingles is a painful rash that occurs anywher...

Shingles, also known as herpes zoster, is a viral infection caused by the varicella-zoster virus, the same virus that causes chickenpox. After a person has had chickenpox, the virus remains dormant in the nerve cells and can reactivate later in li...

Sick building syndrome is believed by some to be an illness caused by unknown agents in buildings. Sick building syndrome is a controversial subject because many experts do not think it is a true syndrome. Sick building sy...

Sweet syndrome is a rare skin disorder characterized by fever, inflammation of the joints (arthritis), and the sudden onset of a rash. The rash consists of bluish-red, tender papules that usually occur on the arms, legs, face or neck, most often o...

Syphilis is a sexually transmitted infection (STI) caused by the bacterium Treponema pallidum. It can be transmitted through sexual contact, including vaginal, anal, and oral sex. Syphilis can also be passed from mother to baby during pregnancy or...

Syphilis is a sexually transmitted disease (STD) caused by an infection with bacteria known as Treponema pallidum. Like other STDs, syphilis can be spread by any type of sexual contact. Syphilis can also be spread from an infected mother to the fe...

Congenital syphilis is a chronic infectious disease caused by a spirochete (treponema pallidum) acquired by the fetus in the uterus before birth. Symptoms of this disease may not become apparent until several weeks or months after birth and, in so...

What are yeast infections? What are commonly known as "yeast" infections are caused by various species of a yeast-like fungus called Candida, particularly the species Candida albicans. Yeast organisms are part of the germs (including bacte...

Grover's disease is a rare, transient skin disorder that consists of small, firm, raised red lesions, most often on the skin of the chest and back. Diagnosis of this disorder becomes apparent under microscopic examination when the loss of the "cem...

Typhoid fever is a bacterial infection caused by Salmonella typhi bacteria. It is a serious illness that can be life-threatening if not treated promptly. Symptoms of typhoid fever include high fever, weakness, stomach pain, headache, and loss of a...

Varicella, commonly known as chickenpox, is a highly contagious viral infection caused by the varicella-zoster virus. It is characterized by an itchy rash with red spots and fluid-filled blisters that typically appear on the face, chest, back, and...

The WAS-related disorders are a spectrum of conditions affecting the immune system that are caused by mutations in the WAS gene. These disorders include Wiskott-Aldrich syndrome, X-linked thrombocytopenia and X-linked congenital neutropenia. The W...

Zika virus is a mosquito-borne virus that is primarily transmitted to humans through the bite of an infected Aedes species mosquito. It can also be transmitted through sexual contact, blood transfusions, and from mother to fetus during pregnancy. ...