A to Z of illnesses

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  • Allergy

    Allergies are caused by the immune system over-reacting to substances in drugs, food, and the environment.  Common allergic responses include rash, sneezing, runny nose, and red or itching eyes.

  • Aspergillosis

    Aspergillosis is infection with a fungus called Aspergillus . This fungus is found throughout the world in a variety of species, usually in decaying vegetation

  • B19 parvovirus

    Parvoviruses are a family of single-stranded DNA viruses. Only parvovirus B19 affects humans. This is the infectious agent that causes fifth disease in children, a mild

  • Bacterial infections

    Information on bacterial infections commonly found in HIV-positive people, including lung, skin and gut infections and sexually transmitted diseases.

  • Blastomycosis

    Blastomycosis is a systemic fungal infection caused by the Blastomyces dermatitidis . Of the endemic systemic mycoses, it is the least common. It is endemic in the mid-western, south-central,

  • Cancer

    Cancers are a range of diseases caused by uncontrolled cell division. A number of cancers occur more frequently among people with HIV than in the general

  • Candidiasis

    Candidiasis is a fungal condition, also known as thrush or candidosis. The most common cause is a very common yeast called Candida albicans, although

  • Cardiomyopathy

    Cardiomyopathy means heart disease of unknown cause. One form of cardiomyopathy called dilated cardiomyopathy, is characterised by poor contraction of the heart muscles. Recent reports

  • Coccidioidomycosis

    Coccidioidomycosis, also known as Valley Fever, is a disease caused by the fungus Coccidioides immitis, which lives in soil in the southwestern US, Mexico, and

  • Cryptococcus

    Cryptococcus neoformans is a yeast-like fungus which is found worldwide, often in soil which has been contaminated by bird excrement. It is much more common

  • Cryptosporidiosis

    Cryptosporidiosis (sometimes called 'crypto' for short – but not to be confused with cryptococcal meningitis) was first reported in humans in 1976. It is caused

  • Cytomegalovirus (CMV)

    Cytomegalovirus (CMV) is a member of the herpes family of viruses. It is relatively common throughout the adult population (up to 50%), but occurs in

  • Depression

    Clinical depression is a medical condition caused by biochemical disorders that interfere with normal functioning and can, in some cases, lead to suicide. It is distinct

  • Diabetes

    Diabetes is a disease where the body does not produce enough, or does not respond to the hormone insulin. This affects the regulation of the

  • Entamoeba histolytica

    Entamoeba histolytica , commonly referred to as amoebas, is a protozoal parasite of the gut which is found in about 5 to 10% of the

  • Giardia lamblia

    Giardia lamblia is a protozoal parasite which infects the upper small intestine causing inflammation. It is a common parasite in the Western hemisphere as well

  • Gingivitis

    Gingivitis literally means inflamed gums. This is a gum disease frequently caused by bacteria and dental hygiene problems. HIV-positive people are more susceptible to gingivitis.HIV-related

  • Guillain-Barré syndrome

    Guillain-Barré syndrome is a paralytic condition caused by damage to the myelin coat that sheaths the nerves. It is a relatively rare condition but can

  • Gynaecomastia (breast enlargement)

    Breast enlargement or gynaecomastia has been reported since 1998 in men and women receiving antiretroviral therapy. Although case reports are rare, its prevalence has not

  • H1N1 influenza

    In response to the 2009 H1N1 influenza ('swine flu') outbreak, guidelines and information on prevention, screening, diagnosis, and treatment have been issued by WHO, the NHS in the

  • Hairy leukoplakia

    Hairy leukoplakia is a condition thought to be caused by the Epstein-Barr virus (EBV), a member of the herpes virus family which is commonly found

  • Hepatitis A

    Hepatitis A is a viral infection that causes inflammation of the liver. It is caused by the hepatitis A virus, also known as HAV. Hepatitis

  • Hepatitis B

    Hepatitis B is a viral infection that can cause serious or even fatal damage to the liver. The word hepatitis literally means inflammation of the

  • Hepatitis C

    Information on hepatitis C, including transmission, treatment and interactions with HIV and anti-HIV treatment.

  • Herpes simplex

    Herpes simplex virus (HSV) is a member of the herpes virus family which also includes varicella zoster virus (VZV) and cytomegalovirus (CMV). HSV is common in

  • Histoplasmosis

    Histoplasmosis is disease caused by the fungus Histoplasma capsulatum, which is common in the south-central United States, South America, central Africa, southeast Asia and Australia

  • HIV-associated dementia

    HIV-associated dementia is one of many terms for impairments in neurological function resulting from HIV infection. There are several terms used for HIV-related brain disease including: AIDS

  • HIV-associated salivary disease

    HIV-associated salivary disease is a relatively benign condition. Dry mouth, dry eyes and enlarged parotid glands (the glands in front of the ears that

  • Hodgkin's disease

    Hodgkin's disease is a type of lymphoma - a tumour of lymph nodes - named after Thomas Hodgkin, a pathologist who first described it in

  • Human herpes virus 6

    Human herpes virus 6 (HHV-6) was first isolated in 1986 from people with AIDS. It has since been found to be relatively common in the

  • Human papillomavirus

    Information on the human papilloma virus, the virus that causes warts and can lead to cervical and anal cancers.

  • Isosporiasis

    Isospora belli is a parasite which belongs to the Coccidia family, which also include Cryptosporidium and Toxoplasma gondii. It is most commonly found

  • Kaposi's sarcoma

    Kaposi's sarcoma (KS) was first described in 1872 by the Hungarian dermatologist Moritz Kaposi. Before the AIDS epidemic it was a rare condition. There are four

  • Lactic acidosis / acidaemia

    Lactic acidosis is a serious side-effect of the nucleoside analogue reverse transcriptase inhibitors (NRTIs), such as AZT (zidovudine, Retrovir) and d4T(stavudine, Zerit). Although rare,

  • Leishmaniasis

    Leishmaniasis is a parasitic infection spread by sandflies, which feed on humans and then inject parasites called mastigotes into the bloodstream or skin. These parasites

  • Lung cancer

    Lung cancer is not an AIDS-defining illness. However, people with HIV have a greater chance of developing lung cancer than non-infected people, and as

  • Lymphocytic interstitial pneumonitis

    Lymphocytic interstitial pneumonitis (LIP) is a lung disorder, also known as lymphoid interstitial pneumonitis/pneumonia, which predominantly occurs in children with HIV. Its cause is still

  • Malaria

    Malaria is a tropical illness caused by parasites called plasmodia. Plasmodia depend on female mosquitoes for part of their life cycle. Most cases of malaria

  • Microsporidiosis

    Microsporidiosis is illness caused by recently discovered protozoan parasites called Microsporidia . The most common of the parasites is Enterocytozoon bieneusi , which infects the

  • Molluscum contagiosum

    Molluscum contagiosum is caused by a common pox virus, producing lesions on the skin. In adults with healthy immune systems the lesions usually appear on

  • Multicentric Castleman's disease

    See Kaposi's sarcoma.

  • Mycobacterium avium intracellulare (MAI)

    Mycobacterium avium and M. intracellulare are very similar bacteria which are usually grouped together. In the United States, they are usually described

  • Mycobacterium haemophilum

    Mycobacterium haemophilum is a mycobacterium, which belongs to the same family of bacteria as the causative agents of M. avium intracellulare (MAI) and tuberculosis.

  • Mycobacterium kansasii

    Mycobacterium kansasii is a bacterium which belongs to the same family as the organisms which cause tuberculosis (M. tuberculosis) and Mycobacterium avium intracellulare (MAI; M.

  • Neuropathy

    Neuropathy means damage to the nerves. The nervous system consists of the central nervous system (CNS), which is comprised of the brain and the spinal

  • Neutropenia

    Neutropenia occurs when the level of neutrophils, a type of white blood cell, falls below normal. The usual range is between 2.5 and 7.5 x

  • Non-Hodgkin's lymphoma

    Non-Hodgkin's lymphoma (NHL) is a type of lymphoma - a tumour that involves the uncontrolled multiplication of a type of white blood cell called lymphocytes.

  • Osteonecrosis

    Osteonecrosis, literally 'bone death', is caused by poor blood supply to an area of bone. Like the other bone disorder osteoporosis, osteonecrosis has only recently

  • Osteoporosis and osteopenia

    Osteoporosis is a condition where the bones lose mass and density. It is commonly referred to as 'thinning of the bones' and occurs most commonly

  • Pancreatitis

    The pancreas is an organ which lies in the abdomen, behind the stomach. It plays an important role in the digestive system by producing enzymes

  • Pelvic inflammatory disease

    Pelvic inflammatory disease (PID) is a common yet complicated condition which affects the upper genital tract, including the Fallopian tubes, ovaries and the ligaments surrounding

  • Penicilliosis

    Penicilliosis is caused by a fungus called Penicillium marneffei. The fungus is widespread in south-east Asia and southern China, but was rarely reported to cause

  • Persistent generalised lymphadenopathy

    Persistent generalised lymphadenopathy (PGL) means having swollen lymph nodes in several parts of the body, which remain swollen for some time. The strict diagnosis of

  • Pneumocystis pneumonia (PCP)

    Pneumocystis pneumonia (PCP) is a lung disease caused by a common organism previously called Pneumocystis carinii , but which has now been renamed P. jiroveci

  • Progressive multifocal leukoencephalopathy (PML)

    Progressive multifocal leukoencephalopathy (PML) is a rare disease of the central nervous system which results in the destruction of the sheath that covers the nerves.

  • Psoriasis

    Psoriasis is a relatively common skin problem. It is an auto-immune condition, which means that the immune system is attacking the body's own cells. People

  • Pulmonary arterial hypertension

    Pulmonary arterial hypertension is a relatively rare, but very serious complication of HIV infection. It is casued by the blood pressure rising in the arteries carrying oxygen-deprived

  • Q fever

    Q fever is a type of fever caused by a rickettsia (a type of micro-organism) called Coxiella burnetti. A small number of people with HIV

  • Salmonellosis

    Salmonellosis is illness caused by Salmonella bacteria, which belong to the family Enterobacteriaceae. The bacteria are transmitted in food and water or sometimes from

  • Schistosomiasis and other worm and fluke infections

    Parasitic worms are a widespread health problem in many tropical and sub-tropical countries. They generally cause chronic illness rather than deaths. They contribute to malnutrition

  • Seborrhoeic dermatitis

    Seborrhoeic dermatitis literally means inflammation of the oil-forming glands in the skin, particularly in hairy parts of the body such as the scalp, chest and

  • Syphilis

    Syphilis is a complex sexually transmitted disease caused by a bacterium called Treponema pallidum . It is transmitted by contact with infected sores or lesions,

  • Testicular cancer

    The incidence of testicular cancer is much higher amongst men with HIV than the rest of the male population. One study suggested an incidence fifty

  • Testosterone deficiency

    Deficiency of the male hormone testosterone, also known as hypogonadism, can cause physical symptoms that clinically may appear to be very close to depression: chronic

  • Thrombocytopenia

    Thrombocytopenia means an abnormally low number of platelets in the blood. Platelets are small cells which are involved in blood clotting. They are quite different from

  • Thrombotic thrombocytopenic purpura

    Thrombotic thrombocytopaenic purpura (TTP) is a rare but serious medical condition. Its incidence is increased in HIV infection, where it is most common in patients

  • Tinea

    Tinea is a fungal infection similar to Candida. Tinea can spread to the hands, nails, lower abdomen and buttocks, groin, thighs or feet, and

  • Toxoplasmosis

    Toxoplasmosis (sometimes called 'toxo' for short) is illness caused by a protozoan called Toxoplasma gondii.

  • Tuberculosis

    Information on tuberculosis, including symptoms, diagnosis, treatment and interactions with HIV and antiretroviral therapy.

  • Ulcers

    People with HIV may develop ulcers in the mouth or oesophagus (throat) that are caused by infections. The commonest cause of oesophageal ulcers is cytomegalovirus

  • Vacuolar myelopathy

    Vacuolar myelopathy is a disease affecting the central nervous system, caused by damage to myelin, the fatty tissue that covers and protects nerves. The myelin

  • Varicella zoster virus

    Varicella zoster virus (VZV), also known as herpes zoster, is a member of the herpes virus family which also includes herpes simplex virus (HSV) and

  • Wasting syndrome

    Involuntary weight loss, or wasting, is one of the most common symptoms of HIV infection. It can occur at any stage of infection and usually

This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.