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Skin Disorders At Any Stage Of HIV Infection
Bacterial infections
Staphylococcus aureus is the most common bacterial pathogen in HIV disease. The bacterium colonises the anterior nares, resulting in nasal carriage in about 50% of HIV-infected patients. A wide range of primary cutaneous and soft-tissue infections occur including folliculitis, ecthyma, impetigo and subcutaneous abscesses. The folliculitis is very common and is the most common cause of follicular pathology. These patients often require prolonged therapy with appropriate anti-staphylococcal antibiotics. Mycobacteria may induce skin lesions in up to 10% of patients with systemic mycobacterial infections. Although tuberculosis commonly presents with extrapulmonary manifestations in advanced HIV disease, cutaneous lesions are still rare but may be seen in miliary disease. Mycobacterium avium-intracellulare is also common in HIV-infected patients, occurring in HIV-infected patients, occurring in up to 25% of cases, but primary cutaneous disease is uncommon. Interestingly the presentation and incidence of leprosy, caused by Mycobacterium leprae, has not been affected by the onslaught of HIV.
Other fungal infections
Diffuse tinea corporis, commonly known as 'ringworm', can occur at any stage of HIV infection but is more extensive and varied in patients with low CD4+ cell counts. Clinically, lesions may lack the typical raised, scaly border and the central clearing. Topical antifungal therapy is initially administered. If clinically unresponsive to topical treatment, oral antifungal agents should be considered. Relapses can occur. Onychomycosis, often proximal white subungual onychomycosis, is common in HIV infection and is only treated if proven mycologically from nail clippings and if patients are symptomatic. Topical or oral antifungal agents are used but relapse tends to be common. Deep fungal infections are increasing in incidence due to the increase in the number of cases of HIV/AIDS, but still remain rare relative to dermatological fungal conditions. Cryptococcal infections cause involvement of the skin via blood-borne invasion in about 6% of cases. The face is the most common site involved (Fig. 6). Lesions can vary from soft flesh-coloured papules to those resembling molluscum contagiosum, and to larger nodules and ulcers. Intravenous amphotericin B followed by long-term fluconazole maintenance therapy is required. Other deep fungal infections which may haematogenously seed the skin include sporotrichosis, histoplasmosis and blastomycosis.
Syphilis
An increased incidence of syphilis has paralleled the HIV epidemic in many countries. For patients with mild-to-moderate immunosuppression cutaneous lesions resemble those of typical primary or secondary syphilis. Diffusely distributed, round to oval, coppery papules which frequently involve the palms and soles are seen in secondary syphilis. However, as the CD4+ count decreases lesions become more bizarre and atypical in morphology. The progression to secondary and tertiary syphilis is more rapid. It has been recommended that primary and secondary syphilis in HIV-seropositive patients be treated with three doses of intramuscular benzathine penicillin at weekly intervals. It must be noted that serological tests for syphilis may be falsely positive or negative, but if syphilis is clinically suspected then a biopsy should be performed on all suspicious lesions.
Cutaneous drug reactions
Adverse cutaneous drug reactions occur in about 10% of HIV-seropositive patients. The most frequently implicated drugs are the sulphonamides and penicillins. Isoniazid, used in the therapy of tuberculosis, also commonly causes skin reactions. Most reactions consist of maculopapular and urticarial rashes. In more advanced disease, severe erythema multiforme minor, Stevens-Johnson syndrome (erythema multiforme major involving mucous membranes), and toxic epidermal necrolysis also occur.
Kaposi's sarcoma
Kaposi's sarcoma can present at any stage of HIV infection but increases in incidence as the CD4+ lymphocyte count decreases. Oral lesions are specifically associated with CD4+ counts below 200 cells/mm3. Initially the lesions are small, flat, purplish patches (Fig.7). These patches become elevated to form plaques and, subsequently, nodules. The colour of the lesions can vary from reddish to purple to brown. Larger infiltrating plaques are associated with lymphoedema. The lymphoedema, especially in the legs, is often misdiagnosed as being due to other causes if the whole involved area of skin is not examined properly. Kaposi's sarcoma can koebnerise where it can be found in old zoster scars, venipuncture sites and contusions. Internal organ involvement, especially of the respiratory and gastrointestinal tracts, is common. It is generally assumed that for every five skin lesions one internal lesion is present. Human herpes virus type 8 (HHV-8) has been associated with Kaposi's sarcoma in both HIV-infected and renal transplant patients. Antiretroviral therapy is associated with clinical improvement, yet whether response is based on increased immunity or antiviral action against HHV-8, or both, is unclear. Both radiation therapy and chemotherapy may be effective treatment modalities for patients with only mild-to-moderate levels of immunosuppression. However, the majority of patients with far-advanced HIV disease and low CD4+ cell counts receive only palliative therapy.
General dermatological changes
As the CD4+ count and level of immunocompetency decreases, the hair becomes lustreless and dull. Straightening of the hair occurs in patients with naturally curly hair. In advanced HIV disease there is a diffuse, fine, downy alopecia, premature graying and elongation of the eyelashes. The nails may be thin, discoloured yellow, or ridged longitudinally. Nail plate pigmentation is frequently seen and may be diffuse or partial, or take the form of longitudinal or transverse bands.
Conclusion
There are many more dermatoses that have been associated with HIV infection but this compilation has dealt with the more commonly encountered skin conditions. It is important for clinicians to recognize these skin changes and to be more alert to the possibility of underlying HIV infection in any patient with dermatological features. As with most diseases seen in HIV/AIDS, the lower the patient's CD4+ cell count the more severe and atypical the dermatological presentation may be. Such presentations can lead to confusion and misdiagnoses. These cases often require further investigations such as skin biopsy, and treatment of HIV-related skin conditions may be difficult. In the face of these difficulties, HIV infection and its challenge to clinical dermatology remains a constant reminder of the continued need to update our general clinical and treatment knowledge.
Further Reading
CME 2000; 18(4): 321-6. Callen JP and Cockerell CJ. Dermatologic Diseases. In: AIDS Therapy, Dolin R, Masur H and Saag MS, Eds. Churchill Livingstone 1999, p 639. Khopkar U. A synopsis of HIV infection and AIDS in India.