Human immunodeficiency virus disease and immunodeficiency syndromes

Human immunodeficiency virus disease and immunodeficiency syndromes


Immunodeficiency results from absence or failure of one or more elements of the immune system. It may be acquired, e.g. acquired immune deficiency syndrome (AIDS), or inherited, e.g. chronic mucocutaneous candidiasis.



Human immunodeficiency virus (HIV) disease


Infection with HIV is a progressive process that mostly leads to the development of AIDS.



Aetiopathogenesis


HIV1 and HIV2 (the latter mainly found in West Africa) are retroviruses containing reverse transcriptase, which allows incorporation of the virus into a cell’s DNA. The virus infects and depletes helper/inducer CD4 T lymphocytes, leading to loss of cell-mediated immunity and opportunistic infection, e.g. with Pneumocystis jiroveci, mycobacteria or cryptococci. HIV is spread by infected body fluids, e.g. blood or semen. High-risk groups for HIV infection include men who have sex with men, intravenous drug users and haemophiliacs who have received infected blood products.



Clinical presentation


The acute infection may be symptomless but, in a variable proportion of cases, seroconversion is accompanied by a non-specific glandular fever-like illness with a maculopapular exanthem on the trunk. HIV infection may be asymptomatic for several years, although most infected individuals will eventually develop symptoms. In the early stages of symptomatic infection, skin changes, fatigue, weight loss, generalized lymphadenopathy, diarrhoea and fever are present without the opportunistic infections that define AIDS. Opportunistic organisms include the ubiquitous Mycobacterium avium complex and Cryptococcus neoformans, and toxoplasmosis and cytomegalovirus.


As the disease progresses, the number of CD4+ lymphocytes falls and, when the blood count is below 50 cells/mL in the late phase of HIV infection (AIDS), M. avium complex infection, lymphoma and encephalopathy may develop. The mean latent period between infection and the development of AIDS is 10 years. Skin signs include the following (Table 1):



image Dry skin. Skin dryness, often with asteatotic eczema, and seborrhoeic dermatitis (Fig. 1) are common and early findings. Their severity increases as the disease advances.


image Fungal and papillomavirus infections. Tinea infections and perianal and common viral warts are seen in early disease.


image Acne and folliculitis. These worsen in early and mid-stage disease.


image Other infections. Oral candidiasis, oral hairy leukoplakia (thought to be associated with Epstein–Barr virus; Fig. 2) and infection with herpes simplex, herpes zoster, molluscum contagiosum and Staphylococcus aureus are increased in advanced disease.


image Other dermatoses. Drug eruptions, hyperpigmentation and basal cell carcinomas are more common; psoriasis can get worse and syphilis may coexist.


image Kaposi’s sarcoma. Kaposi’s sarcoma is a multicentric tumour of vascular endothelium seen in a third of patients with AIDS or AIDS-related complex, particularly in male homosexuals. It presents as purplish nodules or macules on the face, limbs, trunk or in the mouth (Fig. 3), but often also involves the internal organs and lymph nodes. Kaposi’s sarcoma is due to co-infection with herpes virus 8. A more benign sporadic form, seen in elderly East European Jewish men, is not associated with HIV.


image Lymphoma. Lymphomas seen with late-phase HIV infection are often extranodal and sometimes cutaneous.



Table 1 Skin signs and the progressive stages of HIV infection (Centers for Disease Control)

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Apr 20, 2016 | Posted by in Dermatology | Comments Off on Human immunodeficiency virus disease and immunodeficiency syndromes

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