Human Immunodeficiency Virus (HIV) causes the progressive failure of the body’s immune system, making it unable to fight off common infections. Yeast infections, known as Candidiasis, are common fungal infections caused by an overgrowth of Candida species, most frequently Candida albicans. HIV does not directly cause Candidiasis, but it severely compromises the body’s defenses against the fungus. This immune impairment transforms a usually harmless fungus into an aggressive, opportunistic infection that is often more frequent, persistent, and harder to treat.
The Immunological Connection
The link between HIV and an increased risk of Candidiasis lies in the virus’s primary target: the CD4 T-lymphocyte, a type of white blood cell. These helper cells are the directors of the immune response, and a specific subset is responsible for defense against fungal pathogens like Candida albicans. HIV progressively destroys these CD4 T-cells, which leads to a state of immunodeficiency where the body can no longer keep the yeast in check.
This targeted depletion of Candida-specific immune cells happens relatively early in the course of untreated HIV infection, explaining why mucosal Candidiasis is often one of the first opportunistic infections to appear. A low CD4 count, particularly below 200 cells per cubic millimeter of blood, significantly increases the risk of developing Candidiasis in a severe or widespread form. When the immune system is severely compromised, the commensal Candida organism, which normally lives harmlessly on mucosal surfaces, transitions into a pathogen, leading to symptomatic infection.
Clinical Presentation of Candidiasis
Candidiasis in people with advanced HIV infection manifests in specific locations, often signaling the degree of immune suppression.
Oropharyngeal Candidiasis (Thrush)
Oropharyngeal Candidiasis, commonly called thrush, is characterized by creamy white, plaque-like lesions on the tongue, inner cheeks, palate, or throat. This form of Candidiasis is the most common opportunistic infection in HIV-positive individuals and can be an early indicator of immune decline. While the white patches can often be scraped off, the underlying tissue may appear red and sore.
Esophageal Candidiasis
A more serious manifestation is Esophageal Candidiasis, where the infection extends down the tube connecting the throat to the stomach. This condition is often associated with a CD4 count below 200 cells/mm³ and is an AIDS-defining illness. Symptoms typically include retrosternal burning pain, discomfort, and difficulty or pain when swallowing. The presence of oral thrush often prompts suspicion of esophageal involvement.
Vulvovaginal Candidiasis
Vulvovaginal Candidiasis, or a vaginal yeast infection, presents with a thick, white discharge along with itching, burning, and irritation. Unlike the oral and esophageal forms, vulvovaginal candidiasis is common in the general population. However, in HIV-positive women, these infections may be more recurrent or persistent, particularly with advanced immunosuppression.
Treatment and Disease Management
The standard treatment for active Candidiasis involves antifungal medications, with the choice depending on the infection’s location and severity. For mild oropharyngeal cases, topical treatments like clotrimazole lozenges or nystatin suspension may be effective. More moderate or severe cases, including all instances of esophageal candidiasis, require systemic antifungal therapy, most commonly oral fluconazole.
Recurrence is a frequent challenge, and in cases of persistent or severe infection, a longer course of treatment or a different class of antifungal may be necessary. The most effective long-term strategy for preventing recurrent Candidiasis is to restore the function of the immune system.
This is achieved through Antiretroviral Therapy (ART), which is the foundation of modern HIV management. Successful ART suppresses the HIV virus, allowing the CD4 T-cell count to increase and immune function to recover. As the immune system becomes stronger, it naturally regains the ability to control the overgrowth of C. albicans, dramatically reducing the frequency and severity of opportunistic infections like Candidiasis. Frequent recurrence of Candidiasis can signal that the HIV is poorly controlled, necessitating a review or adjustment of the ART regimen.