HIV does not directly cause “black spots” on the skin, but the resulting immune compromise leads to various secondary health issues, many of which manifest as skin changes. HIV is a chronic condition that progressively compromises the body’s immune defenses. Skin changes, including hyperpigmentation or dark lesions, are frequently observed in people living with HIV (PLHIV). Understanding the cause of these spots requires distinguishing between effects of the weakened immune system, opportunistic infections, and side effects of necessary medications.
Understanding the Link Between HIV and Skin Health
HIV itself does not typically cause discrete black spots directly, but it creates the underlying conditions for dark lesions to appear. The virus targets and destroys CD4+ T-cells, which are the primary orchestrators of the immune response. This progressive depletion of CD4+ cells leads to a state of immunosuppression, which is the root cause of most HIV-related skin conditions.
This compromised immune state allows various external and internal factors to cause skin changes, including hyperpigmentation. The body’s inflammatory response can lead to increased levels of alpha-melanocyte-stimulating hormone (\(\alpha\)-MSH). Since \(\alpha\)-MSH controls the production of melanin, this hormonal shift can potentially lead to generalized skin darkening or hyperpigmentation as a secondary effect. Therefore, the dark spots are usually a symptom of a secondary condition thriving in an immunocompromised environment or a side effect of treatment, not a direct viral lesion.
Kaposi’s Sarcoma and Other Opportunistic Lesions
The most serious cause of dark, discolored spots in the context of advanced HIV is Kaposi’s Sarcoma (KS), a form of cancer. KS is caused by Human Herpesvirus 8 (HHV-8), which the weakened immune system cannot control. This cancer is considered an AIDS-defining illness, meaning its presence often indicates a severely compromised immune system, typically with a very low CD4 count.
The lesions of Kaposi’s Sarcoma are tumors that develop from the cells lining blood or lymph vessels. They commonly appear as patches, plaques, or nodules on the skin, ranging in color from pink or red to purple, brown, or black, often resembling bruises. While they often appear on the skin, they can also affect mucosal surfaces like the mouth, or internal organs such as the lungs and digestive tract, which can be life-threatening. The widespread use of effective Antiretroviral Therapy (ART) has dramatically reduced the incidence of KS, but it remains a concern for individuals with undiagnosed or untreated HIV.
Beyond KS, a weakened immune system also makes people susceptible to other opportunistic infections that can cause dark or atypical lesions. For example, bacillary angiomatosis, caused by Bartonella bacteria, can present as hyperpigmented red or purple papules and nodules. Certain fungal or viral infections can also result in lesions that become hyperpigmented as they heal, or if they present in a more severe manner due to immunosuppression. These opportunistic lesions highlight that the dark spots are indicators of a vulnerability caused by the virus, not the virus itself.
Antiretroviral Therapy and Hyperpigmentation
A separate, non-infectious cause of skin darkening is a side effect of some Antiretroviral Therapy (ART) medications. Certain drugs used in the treatment regimen can cause benign hyperpigmentation, which is a sign of treatment rather than disease progression. This side effect is a known adverse reaction, though its prevalence and severity vary depending on the specific medication.
The older class of drugs known as Nucleoside Reverse Transcriptase Inhibitors (NRTIs), particularly zidovudine (AZT), have historically been associated with this darkening. Hyperpigmentation due to ART can manifest in several ways, often appearing as diffuse darkening of the skin, or more specifically in the nails, gums, or oral mucosa. The mechanism is thought to involve either the drug directly depositing in the skin or stimulating melanin production.
While the cosmetic changes can be concerning, drug-induced hyperpigmentation is usually harmless. Nail pigmentation, for example, can appear as longitudinal bands and is generally reversible upon discontinuation of the causative drug, although the process can take a long time. A healthcare provider may adjust the ART regimen to alleviate this side effect, which is often a greater concern for patients with naturally darker skin tones.
When to Consult a Healthcare Provider
Any new or changing skin lesion in a person with HIV should prompt a medical evaluation without delay. While many skin changes are benign, only a healthcare professional can accurately determine the underlying cause. Self-diagnosing a dark spot as harmless could delay the diagnosis of a serious condition like Kaposi’s Sarcoma.
It is particularly important to seek urgent medical advice if a dark spot or lesion is growing rapidly, begins to bleed, becomes painful, or is accompanied by systemic symptoms. Unexplained fever, weight loss, or difficulty breathing combined with new skin spots are warning signs requiring immediate attention. Prompt medical assessment ensures that appropriate treatment can be initiated quickly, whether for an opportunistic infection, a malignancy, or a medication side effect.