Page 244 - AIDSBK23C

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Acanthamebiasis, though rare, is most likely to involve the skin in patients with AIDS
and can lead to the appearance of pustules, indurated papules or plaques, ulcers, and
cellulitis.[540]
Hansen disease (leprosy) does not appear to occur more frequently in persons infected with
HIV, even in areas where Hansen disease is endemic, nor is there an increased HIV prevalence
among leprosy cases. There does not appear to be an alteration in clinical spectrum of leprosy
among coinfected patients. HIV does not appear to accelerate existing Mycobacterium leprae
infections. Borderline tuberculoid leprosy is the most common clinical form. However, some
patients may have less common chronic, hyperkeratotic, eczematous lesions. Interestingly,
persons with a low CD4 lymphocyte count appear able to maintain a granulomatous response to
M leprae. Use of antiretroviral therapy appears to reduce numbers of M leprae organisms.
However, some patients have a worsened course from immune reconstitution inflammatory
syndrome (IRIS).[989,990]
Syphilis from infection with Treponema pallidum may present as a primary form with
chancre and as a secondary form with maculopapular rash. Persons with HIV infection are more
likely to exhibit lues maligna with secondary syphilis. Lues maligna (ulceronodular syphilis)
exhibits a papulopustular skin lesion with well-demarcated borders, sometimes covered with a
lamellar crust.[991]
Skin lesions are characteristic findings of Mycobacterium haemophilum infection. These
lesions tend to cluster on extremities and over joints where cooler ambient temperatures favor
growth of these organisms. Septicemia is common, and the hematogenous dissemination allows
M haemophilum to be cultured from a variety of body fluids and tissue sites. Joint involvement
may produce arthralgia.[448] Mycobacterium fortuitum infection may present as subcutaneous
nodules with necrosis in persons whose risk factor for HIV infection is injection drug use. Other
mycobacterioses seen with AIDS such as M avium complex and M tuberculosis are unlikely to
have cutaneous involvement.[972]
Skin testing that relies upon delayed-type hypersensitivity reactions can still be
performed in HIV-infected persons. For children, the skin test reactions are qualitatively very
similar to those seen in age-matched control subjects, though anergy with loss of responsiveness
suggests a progression to AIDS. In adults with AIDS, the interpretation of tuberculin skin
testing may need to be modified due to partial loss of cell-mediated immunity. About 10% of
persons with a CD4 lymphocyte count >500/µL are likely to exhibit anergy, though a positive
test in HIV-infected persons should be defined as any area of induration >0.5 cm (or >0.2 cm for
injection drug users).[208,237]
Cutaneous lymphomas can be seen with AIDS, typically at a later stage of disease. They
are either CD30+ T-cell lymphomas or diffuse large B-cell lymphoma. Mycosis fungoides is
rare in persons with AIDS. Cutaneous lymphomas in AIDS are typically localized nodules.[576]
Late in the course of AIDS, cutaneous eruptions termed pseudolymphomas that histologically
consist of a dense infiltrate of lymphocytes resembling cutaneous T-cell lymphoma may occur.
Grossly they may mimic mycosis fungoides with erythroderma, disseminated papules, pustules,
plaques, or nodules. However, the CD8 lymphocytes that comprise these infiltrates are
polyclonal and accompanied by eosinophils, plasma cells and rare neutrophils. The
pseudolymphoma may have a psoriasiform lichenoid pattern with limited epidermal infiltration
by small lymphocytes, a superficial and deep perivascular and perifollicular pattern or an
interface pattern with normal epidermal thickness.[982]