AIDS was first described in 1981 and since then 22 million people have died of the disease.
The World Health Organisation estimates that in December 2000, 36 million people were infected with HIV.
Of these, 1·5 million were children under the age of fifteen. It is estimated that 5·3 million people were newly infected with HIV in the year 2000 and 3 million have died in the same year.
A total of nearly 22 million people have died of AIDS since the start of the epidemic.
In the United Kingdom the prevalence of HIV infection is about 30 000. Over 65 000 in Europe are infected.
The human immunodeficiency virus (HIV) is the cause of the acquired immunodeficiency syndrome (AIDS).
This virus was first isolated in 1983 in Paris and a second retrovirus, HIV2, was isolated from West Africa in 1986.
The virus contains an enzyme that copies viral RNA into the DNA of the host cell in which the HIV virus then persists in the host cells, particularly monocytes, macrophages, and dendritic cells.
Stages of AIDS
Primary HIV infection
In 80% of cases there are initial symptoms and signs “seroconversion illness”.
There are a variety of symptoms including fever, malaise, headache, nausea, vomiting, and diarrhoea.
There is often lymphadenopathy.
The skin signs consist of a transient maculopapular eruption associated with erythema and erosions in the mouth in some patients. Early stages
In the early stages 50% of patients have antibiotics to HIV and the p24 antigen can be detected.
The proportion of CD4 lymphocytes decreases, and this is associated with the development of secondary changes in the skin.
There is also an increase in HIV antibodies so a test for this should be repeated six to eight weeks after the initial illness. Counselling should take place before testing is carried out.
Late stage HIV disease
The skin changes are many and variable.
Common inflammatory skin diseases such as psoriasis and seborrhoeic dermatitis will be much more florid.
Cutaneous infections are more severe due to the impaired immune response and opportunistic infections also develop.
In addition, Kaposi’s sarcoma occurs in 34% of homosexual men and in 5% of other cases.
AIDS should therefore be considered in any patient with a florid inflammatory skin disease that is resistant to treatment or severe and extensive infection of the skin.
Skin changes in AIDS
Seborrhoeic eczema
This is common and may be the only evidence of HIV infection initially.
It is more extensive and inflamed than usual.
The role of Pityrosporum organisms is indicated by the response to imidazole antifungal drugs.
Psoriasis
Psoriasis is more widespread, severe, and resistant to treatment in patients with late HIV disease.
The use of ultraviolet light may lead to an increased risk of Kaposi’s sarcoma.
Infections
Any type of opportunistic infection is more likely in patients with AIDS and will generally be more severe. An itching, inflammatory folliculitis occurs in many cases.
The cause is unknown, but it is possible that Demodex spp. play a part.
Fungal infections
Superficial fungal infections are often much more extensive and invade more deeply into the dermis than usual.
There may also be granuloma formation.
Deep fungal infections that are not normally seen in healthy individuals occur in AIDS patients as opportunistic infections.
Cryptococcus neoformans and Histoplasma capsulatum may cause inflammatory papular and necrotic lesions, particularly in the later stages of the disease.
Candidiasis is common and often associated with bacterial infections.
It occurs particularly in and around the mouth, on the palate, and in the pharynx.
It commonly causes severe vulvovaginitis in infected women. Pityrosporum organisms occur more frequently and may produce widespread pityriasis versicolor on the trunk or extensive folliculitis.
Bacterial infections
Impetigo may be severe, with particularly large bullous lesions occurring.
Mycobacteria may produce widespread cutaneous and systemic lesions.
Varieties of mycobacteria that do not normally infect the skin may cause persistent necrotic papules or ulcers.
Viral infections
Both herpes simplex and herpes zoster infections may be unusually extensive, with large individual lesions.
In the case of herpes zoster the affected area may extend beyond individual dermatomes.
Sometimes persisting ulcerated lesions occur.
Molluscum contagiosum lesions are frequently seen.
They are much larger than usual and develop over quite large areas of skin.
They are readily identified as small, firm papules with an umbilicated centre.
When very large individual molluscum lesions occur they may be due to localised fungal infection, particularly cryptococcus and histoplasmosis. Viral warts may be large and extensive.
Perianal and genital warts due to the human papilloma virus (HPV) are common and may be associated with intraepithelial neoplasia of the cervix and sometimes invasive perianal squamous cell carcinoma.
The warts tend to become smaller as the immune status of the patient improves with the treatment.
It is not unusual for florid viral warts to develop in the mouth.
Other manifestions
Oral hairy leukoplakia occurs in 30–50% of patients with AIDS.
It is characterised by an overgrowth of epithelial plaques on the sides of the tongue with a verrucous surface and a grey/white colour.
It is believed to be due to a proliferation of the Epstein–Barr virus.
Infestations with various organisms is not uncommon and the severe widespread crusted lesions of Norwegian scabies may occur.
Kaposi’s sarcoma
Kaposi’s sarcoma is associated with the later stages of AIDS but can occur earlier.
It is associated with herpes virus type 8.
It often presents with small polychromic macules on the face, palate, trunk or groin which vary from red and purple to brown.
They then develop into larger livid plaques, involving the trunk, limbs, and face, and also the oral mucosa.
They are most common on the palate and nose.
Sometimes the lesions are very aggressive. B cell lymphoma may occur in the skin in 10% of AIDS patients.
There is also an increased incidence of basal cell and squamous carcinomas.
Drug rashes
Reactions to sulphonamides and antibiotics are not uncommon, usually presenting as a maculopapular eruption.
Occasionally this can be severe and associated with Stevens–Johnson syndrome.
Myopathy may occur as a reaction to zidovudine.
All the above manifestions of AIDS become less marked as the CD4 count improves with treatment.
AIDS may thus present with a wide variety of skin conditions, commonly with several present at the same time.
Any unusually florid skin condition that is resistant to treatment should raise the suspicion that HIV infection may be present.
