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HIV / AIDS Symptoms & Complications

Medically reviewed by L. Anderson, PharmD Last updated on Feb 26, 2017.

What is HIV Infection?

Once the Human Immunodeficiency Virus (HIV) has entered the body, the immune system comes under attack. The HIV virus multiplies and slowly begins to destroy the CD4 lymphocytes (T-cells), which are the white blood cells that are important for fighting off infections. Even if the person with HIV feels well with no symptoms, HIV is still invading the CD4 cells. The immune system weakens progressively over time and becomes susceptible to bacterial, viral, fungal and parasitic (opportunistic) infections.

As more serious symptoms and complications appear, the HIV infection may then meet the official definition of AIDS: a positive HIV-antibody ELISA followed by a confirmatory Western Blot test or other HIV virologic test (HIV nucleic acid test, HIV p24 antigen test, HIV viral culture) and either the onset of an "AIDS-defining" infection or cancer, or a CD4 T-cell count of 200 cells/mm3 - a normal count ranges from 600 to 1000 cells/mm3 - or a CD4 T-cell percentage of total lymphocytes of <14.

Antiretroviral therapy (ART) is the backbone of HIV treatment today and is necessary to help prevent possible life-threatening opportunistic infections and AIDS-related illnesses and cancers. 

How is AIDS defined?

If a person infected with HIV has:

  • CD4 count of less than 200 cells/mm3
  • a CD4+ T-lymphocyte percentage of total lymphocytes of less than 14%
  • and/or an AIDS-defining illness

they are said to have AIDS. In order for a patient who is infected with HIV to have AIDS, the immune system must be severely damaged. The severity of the immune system damage is measured by a CD4 lymphocyte (white blood cell) count. Patients are at greatest risk of developing opportunistic infections when the CD4 count gets below 200 cells/mm3.

Common HIV Symptoms

It is common to develop a brief flu-like illness 2 to 6 weeks after being infected with HIV. The symptoms may include:

  • Fever
  • Headache
  • Sore throat
  • Swollen lymph glands
  • Rash

These symptoms are similar to many other diseases and may not be recognized as HIV infection initially.

Initial infection with the HIV virus may produce little to no symptoms. The length of time between initial HIV infection and the development of AIDS varies greatly and some people may remain without symptoms for years. However, even though a person does not have symptoms, they can still transmit the virus to others.

Many people remain symptom free for 10 years or longer but during this time the virus continues to multiply and destroy their immune cells for people who are not on antiretroviral therapy (ART). The Centers for Disease Control (CDC) states the following may be warning signs of HIV infection but cautions that any of these symptoms can be related to other illnesses and that only an HIV blood test can be used for an accurate diagnosis:

  • Rapid weight loss
  • Dry cough and shortness of breath
  • Recurring fever or profuse night sweats
  • Profound and unexplained fatigue
  • Swollen lymph glands in the armpits, groin, or neck
  • Diarrhea that lasts for more than a week
  • White spots or unusual blemishes on the tongue, in the mouth, or in the throat
  • Pneumonia
  • Red, brown, pink, or purplish blotches on or under the skin, or inside the mouth, nose, or eyelids
  • Memory loss, depression, or other neurological disorders.

During the last phase of HIV, which can occur up to 10 or 11 years after the initial infection, the immune system will have been severely damaged, making the body highly susceptible to a large number of bacterial, viral, fungal and parasitic (also called opportunistic) infections.

The symptoms of some of these infections may include:

  • Shaking chills or fever higher than 100 F for several weeks
  • Soaking night sweats
  • Dry cough and shortness of breath
  • Chronic diarrhea
  • Persistent white spots or unusual lesions on the tongue or in the mouth
  • Persistent headaches
  • Blurred and distorted vision
  • Weight loss
  • Persistent, unexplained fatigue
  • Swelling of lymph nodes for more than three months

People with HIV infection are also at greater risk of developing certain cancers, especially Kaposi's sarcoma, cervical cancer and lymphoma.

What is the Difference Between AIDS-Defining Illness and Opportunistic Infection?

AIDS-defining illnesses tend to occur most often in patients who have not received antiretroviral treatment (ART) for HIV infection or who fail to benefit from antiretroviral treatment. AIDS-defining illnesses, as defined by the CDC, are directly linked with the deterioration of the immune system as a result of HIV infection.

AIDS-defining illnesses can also be classified as opportunistic infections, but the opposite is not always true. Opportunistic infections occur from agents like viruses, bacteria and fungi that only cause disease when the immune system is weak, as with HIV/AIDS. AIDS-defining illnesses tend to occur in the later stage of the disease with a very low CD4 count. On the other hand, opportunistic infections may occur with high white blood cell counts and are not always life-threatening.

List of AIDS-Defining Illnesses in HIV/AIDS

The Centers for Disease Control (CDC) considers the following list of conditions as "AIDS-defining". Many other illnesses and corresponding symptoms may develop in addition to those listed here:

  • Bacterial infections, multiple or recurrent
  • Candidiasis of bronchi, trachea, or lungs
  • Candidiasis of esophagus
  • Cervical cancer, invasive
  • Coccidioidomycosis, disseminated or extrapulmonary
  • Cryptococcosis, extrapulmonary
  • Cryptosporidiosis, chronic intestinal (>1 month's duration)
  • Cytomegalovirus disease (other than liver, spleen, or nodes), onset at age >1 month
  • Cytomegalovirus retinitis (with loss of vision)
  • Encephalopathy, HIV related
  • Herpes simplex: chronic ulcers (>1 month's duration) or bronchitis, pneumonitis, or esophagitis (onset at age >1 month)
  • Histoplasmosis, disseminated or extrapulmonary
  • Isosporiasis, chronic intestinal (>1 month's duration)
  • Kaposi sarcoma
  • Lymphoid interstitial pneumonia or pulmonary lymphoid hyperplasia complex
  • Lymphoma, Burkitt (or equivalent term)
  • Lymphoma, immunoblastic (or equivalent term)
  • Lymphoma, primary, of brain
  • Mycobacterium avium complex or Mycobacterium kansasii, disseminated or extrapulmonary
  • Mycobacterium tuberculosis of any site, pulmonary, disseminated, or extrapulmonary
  • Mycobacterium, other species or unidentified species, disseminated or extrapulmonary
  • Pneumocystis jirovecii pneumonia
  • Pneumonia, recurrent
  • Progressive multifocal leukoencephalopathy
  • Salmonella septicemia, recurrent
  • Toxoplasmosis of brain, onset at age >1 month
  • Wasting syndrome attributed to HIV

List of Common Opportunistic Infections in HIV/AIDS

The symptoms of AIDS are primarily the result of infections (opportunistic infections) that do not normally develop in individuals with healthy immune systems.

  • Candidiasis (fungal infection) of the bronchi, trachea, esophagus, or lungs
  • Coccidioidomycosis - a type of fungal pneumonia due to Coccidioides immitis
  • Cryptococcosis - fungal infection due to Cryptococcus neoformans
  • Cryptosporidiosis - diarrheal disease is caused by the protozoan parasite Cryptosporidium
  • Cytomegalovirus diseases - may affect eye (can lead to blindness with CMV retinitis), lungs, stomach
  • Encephalopathy, HIV-related - brain disease
  • Herpes simplex virus infection (HSV)
  • Histoplasmosis - fungal lung infection due to Histoplasma capsulatum
  • Isosporiasis, chronic intestinal
  • Invasive cervical cancer
  • Kaposi's Sarcoma
  • Lymphoma, multiple forms
  • Mycobacterium avium complex (MAC), or other Mycobacterium infections
  • Pneumocystis jiroveci pneumonia (PCP) - fungal lung infection previous called Pneumocystis carinii
  • Pneumonia, recurrent
  • Progressive multifocal leukoencephalopathy
  • Salmonella septicemia, recurrent
  • Toxoplasmosis of the brain
  • Tuberculosis
  • Wasting syndrome due to HIV

are some of the most common HIV-related opportunistic infections seen in clinical practice.

HIV Symptoms in Children

Children who are HIV positive often fail to gain weight or grow normally. As the disease progresses, they may have difficulty walking or delayed mental development, or cerebral palsy. In addition, children are susceptible to the same opportunistic infections as adults and may have severe forms of common childhood illnesses such as ear infections (otitis media), pneumonia, and tonsillitis.

Tuberculosis (TB)

Tuberculosis is the most common opportunistic infection associated with HIV worldwide. Tuberculosis is an infection by the tuberculosis bacterium that predominantly affects the lungs, but it can spread through the blood and lymph nodes to the rest of the body in people with HIV.

TB causes a long-term cough that may produce blood and may also cause fever, weight loss and night sweats. The disease can strike people with HIV no matter what the level of their CD4 count, which means that TB can often occur years before other problems associated with HIV develop.

Everyone who is HIV-positive should have a simple skin test for TB. If the test is positive, a chest X-ray and other tests will determine if the infection is active. If the TB is not active, preventative treatments are available.

Tuberculosis is more worrisome than many other opportunistic infections because of the ease with which it is spread (by coughing or sneezing) from one person to another. Multi-drug Resistant-Tuberculosis (MDR-TB) is resistant to traditional treatments and is of particular concern to people with HIV and AIDS.

Anyone with HIV can get Tuberculosis but it is more likely to occur in those with CD4 counts of less than 200 cells/mm3 .

Herpes Simplex Virus (HSV)

Herpes Simplex virus, which usually causes genital herpes, may be transmitted during unprotected sex. Initial symptoms include pain or irritated skin in the genital area and later sores that may erupt and ooze and bleed. Although these sores eventually heal, the virus periodically reappears, causing the same symptoms.

The symptoms of HSV are more severe in people with HIV and the sores may take longer to heal (over one month in duration). The herpes virus isn't life-threatening in adults, but it may cause brain damage, blindness or death in infants infected during delivery.

Anyone with HIV can get Herpes Simplex, regardless of their CD4 count.

Candidiasis in HIV

Candidiasis (thrush) is a yeast infection of the mouth or genitals and is a very common HIV-related infection. The symptoms include inflammation and a thick white coating on the mucous membranes of the mouth, tongue, vagina or esophagus (Candida esophagitis). Children may have especially severe symptoms in the mouth or esophagus, which can make eating painful and difficult. Uncomplicated, severe or recurrent vulvovaginal candidiasis may also occur.

Candidiasis of the bronchi, trachea, lungs or esophagus is considered "AIDS-defining", but oral or vulvovaginal candidiasis are not considered "AIDS-defining".

Anyone with HIV can get Candidiasis but it is more dangerous in those with CD4 counts of less than 200 cells/mm3.

Read More: Candidiasis Health Guide

Lymphomas in HIV

Non-Hodgkin's Lymphoma (NHL) is a cancer of the lymph glands originating in the lymphocytes, a type of white blood cell involved in fighting infection. NHL usually starts in the lymph nodes but can also start in the liver, lungs or gastrointestinal tract. The most common symptom of NHL is swollen (usually painless) lymph nodes in the neck, armpit or groin. Other symptoms include fever, night sweats, fatigue, itchy skin and weight loss, aches, and sometimes coughing, difficulty breathing and chest pain.

Non-Hodgkin lymphoma has become more common in the past few decades. This may be related to the rise in the number of people who have a suppressed immune system, such as people infected with human immunodeficiency virus (HIV) and those who have had an organ transplant and need to take drugs that alter the immune system.

Other AIDS-defining lymphomas include Burkitt’s Lymphoma and Brain Lymphoma.

Anyone with HIV can get Non-Hodgkin's Lymphoma but it is more likely in those with CD4 counts of less than 200 cells/mm3 .

Salmonella in HIV

Salmonellosis (food poisoning) is an infection caused by the salmonella bacterium, which is contracted from contaminated food or water. Symptoms include severe diarrhea, fever, chills, abdominal pain and sometimes vomiting. The risk of contracting salmonellosis can be reduced by hand washing and by cooking meat and eggs thoroughly.

Salmonella septicemia usually is treated with antibiotics. Drug therapy may be required for life to prevent relapses. HIV patients should avoid having reptiles as pets due to the possible transmission of salmonella.

Anyone with HIV can get Salmonellosis, regardless of their CD4 count.


Human Papillomavirus (HPV) is one of the most common causes of sexually transmitted disease. Some types of this virus cause common warts while others cause warts on the genitals. HPV infection is especially serious because it puts women at risk of invasive cervical cancer; the risk is further increased in women with HIV.

Anyone with HIV can get Human Papillomavirus but women with CD4 counts of less than 50 cells/mm3 are more likely to develop HPV-related growths in the cervix.

Cryptosporidiosis in HIV

Cryptosporidiosis is an infection contracted by ingesting contaminated food or water. The parasite grows in the intestines and bile ducts and can cause severe chronic diarrhea. Symptoms are chronic in patients with AIDS, lasting longer than one month.

Anyone with HIV can get Cryptosporidiosis; however, it is particularly dangerous for those with a CD4 count of 50 cells/mm3 or less.

Pneumocystis Jiroveci Pneumonia (PCP) in HIV

Pneumocystis Jiroveci Pneumonia, also known as Pneumocystis Carinii Pneumonia (PCP) is the most common opportunistic infection that occurs with AIDS in the United States. The fungus that causes the PCP infection is spread through breathing or coughing. Symptoms include persistent cough, fever, trouble breathing (lips and nail-beds may become blue), fatigue, and weight loss. Medication such as sulfamethoxazole/trimethoprim is frequently used to treat and prevent PCP.

PCP is particularly dangerous for those with a CD4 count of less than 200 cells/mm3 .

Recurrent Pneumonia in HIV

Studies have shown that persons with HIV-related immunosuppression are at an increased risk of bacterial pneumonia. Recurrent episodes of pneumonia (two or more episodes within a 1-year period) are required for AIDS case reporting because pneumonia is a relatively common diagnosis and multiple episodes of pneumonia are more strongly associated with immunosuppression than are single episodes.

Patients with CD4 counts less 200 cells/mm3 may be at higher risk of recurrent episodes of pneumonia.

Kaposi's Sarcoma (KS) in HIV

Kaposi's Sarcoma is the most common AIDS-related cancer. It is a tumor of the blood vessel walls. Common symptoms are pink, red or purple lesions on the skin and in the mouth. The first spots, sores or bumps usually appear on the face, nose, mouth, arms, upper body or legs. The lesions vary from pinhead size to the size of a large coin and may be painless. Sometimes the skin lesions are painful and can cause itching and sores in the mouth or throat may cause eating or swallowing problems. Kaposi's sarcoma can also affect the internal organs, including the digestive tract, lymph nodes and lungs.

Anyone with HIV can get Kaposi's Sarcoma, but it is more likely in those with CD4 counts of less than 200 cells/mm3.

Coccidioidomycosis in HIV

A fungal infection that progresses to chronic localized disease of the lungs or other organs such as bone, skin, and meninges. Lung involvement is most common in patients with AIDS.

Learn More: Compare drugs associated with Coccidioidomycosis

Cryptococcal Meningitis in HIV

Cryptococcal meningitis, caused by a fungus, is the most common central nervous system infection associated with HIV. Meningitis is an inflammation of the membranes and fluid surrounding the brain and spinal cord (meninges). Symptoms include headache, high fever, stiff neck, and sensitivity to light. Meningitis is a serious disease that can cause severe complications and even prove fatal in a short amount of time.

Cryptococcal Meningitis is particularly dangerous in those with a CD4 count of 50 cells/mm3 or less.

Toxoplasmosis in HIV

Toxoplasmosis, caused by a parasite spread primarily by cats, is the most common cause of brain lesions in people with advanced HIV disease where toxoplasmosis often leads to encephalitis, an infection of the brain. Symptoms may include disorientation, seizures, fatigue, headaches and difficulty walking or speaking.

Toxoplasmosis is particularly dangerous in those with a CD4 count of 100 cells/mm3 or less.

Progressive Multifocal Leukoencephalopathy (PML) in HIV

Progressive Multifocal Leukoencephalopathy (PML) is an extremely serious viral disease of the brain. PML causes a quick decline in cognitive and motor functions. Symptoms vary and may include speech problems, weakness on one side of the body, loss of vision in one eye, or numbness in one arm or leg. PML is a late-stage disease that occurs only when the immune system is severely damaged.

Mycobacterium Avium Complex (MAC) in HIV

Mycobacterium Avium Complex is a common AIDS infection caused by a bacterium related to tuberculosis. Normally, the bacterium causes an infection of the respiratory tract but, in advanced HIV or AIDS, a systemic infection can affect almost any internal organ, including the bone marrow, liver or spleen. MAC causes nonspecific symptoms such as cough, fever, night sweats, weight loss, fatigue, stomach pain, and diarrhea.

MAC is particularly dangerous in those with a CD4 count of 50 cells/mm3 or less.

Cytomegalovirus (CMV) in HIV

Cytomegalovirus infection (CMV) is a viral infection that can affect almost any organ system. A healthy immune system inactivates the virus and it therefore remains dormant in the body. If the immune system weakens, as in untreated HIV, the virus resurfaces. Symptoms include fatigue, fever, enlarged lymph nodes and pain in the muscles or throat. CMV can cause damage to the eyes (retinitis), digestive tract (diarrhea), lungs (pneumonia), liver (hepatitis), or other organs.

CMV is particularly dangerous in those with a CD4 count of 50 cells/mm3 or less.

Other Conditions and Complications

  • AIDS Related Wasting Syndrome - Extreme weight loss and anorexia caused by HIV.
  • AIDS Dementia - Worsening and slowing of mental function caused by HIV.
  • Encephalopathy, HIV-related - Damage to the brain due to HIV disease. It may result in a form of dementia in advanced HIV disease.
  • Histoplasmosisa fungal infection caused by Histoplasma capsulatum, which primarily affects the lungs or other organs.
  • Isosporiasis - caused by infection with a species of Isospora; can lead to intractable diarrhea.

See Also


  • Division of HIV/AIDS Prevention; Centers for Disease Control and Prevention (CDC). Opportunistic Infections. Accessed Feb. 26, 2017 at
  • What is HIV/AIDS? Accessed Feb. 26, 2017 at
  • University of California San Francisco. AIDS
    Diagnosis. Accessed Feb. 26, 2017 at
  • Opportunistic Infections. Accessed Feb. 26, 2017 at
  • Opportunistic Infections. Accessed Feb. 26, 2017 at

Further information

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