Page 238 - AIDSBK23C

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CRUSTED (NORWEGIAN) SCABIES.-- Crusted (Norwegian) scabies, a highly
contagious infestation of the mite Sarcoptes scabiei, can appear in patients with AIDS. Unlike
skin involvement with acute eruption seen with ordinary scabies in immunocompetent persons,
with crusted scabies the onset is insidious and the pattern of distribution of lesions involves
scalp, face, back, and nails. In its classic form, there are severe extensive hyperkeratotic
nonpruritic lesions that appear as horny plaques from 3 to 15 mm in size. Lesions may also
appear as a papular, pruritic dermatitis. They can also be erythematous or psoriasiform.
Microscopically, the hyperkeratotic, parakeratotic, and acanthotic lesions contain numerous
mites in subcorneal burrows. The lesions can become secondarily infected, often with
Staphylococcus aureus, with further complication of septicemia. Diagnosis is made by skin
scraping, particularly with sampling under fingernails, and if negative, with biopsy of a non-
excoriated region. Laboratory studies may reveal peripheral eosinophilia and elevated IgE levels
in over half of patients. Treatment with scabicides is effective, but must be continued for a
longer time frame than for ordinary cases of scabies. The lesions of crusted scabies are quite
contagious and health care workers can become infected, so strict isolation and containment
practices are needed.[976,977]

BACILLARY ANGIOMATOSIS. -- Bacillary angiomatosis, or epithelioid angiomatosis,
is caused by fastidious gram-negative bacilli of the species Bartonella henselae (formerly
Rochalimaea henselae). Clinically, this lesion may appear as multiple violaceous subcutaneous
nodules or angiomatous papules. Histologically it is characterized by a pseudoneoplastic
proliferation of dilated vascular channels in a circumscribed pattern resembling a pyogenic
granuloma, but is distinguished by the presence of large plump, protuberant, occasionally
atypical endothelial cells. These endothelial cells have an “epithelioid-like” appearance and
often project into vessel lumens to give a tombstone-like appearance. The lesion differs from
Kaposi's sarcoma by the presence of neutrophils with leukocytoclasis, by the absence of spindle
cells or hyaline globules, and by resolution with antibiotic therapy (erythromycin).[491,510,978]

ACUTE HIV INFECTION. -- More than half of persons have symptoms associated with
initial HIV infection, known as acute retroviral syndrome, though these manifestations are non-
specific and resemble a flu-like illness or infectious mononucleosis-like illness.[193] About
75% of persons with acute retroviral syndrome will develop cutaneous manifestations, typically
an exanthem characterized by erythematous papules and macules on trunk and extremities, and
sometimes the palms and soles. This rash lasts for about 4 to 5 days and then resolves
completely. Seroconversion occurs later.[972]

BACTERIAL INFECTIONS.-- Staphylococcus aureus is the most common cutaneous
bacterial pathogen in HIV-infected patients, because of significant rates of nasal carriage of S.
aureus. Staphylococcal infection may produce furuncles, carbuncles, or abscesses characterized
by erythematous, tender, and indurated lesions. Impetigo may exhibit honey-colored crusts or
bullous lesions. The term botryomycosis describes a chronic, granulomatous, suppurative S.
aureus infection that usually occurs following skin trauma and causes subcutaneous nodules to
plaques with ulcers, purulent secretions, fistulae, and “sulfur like” grains in secretions. Lesions
of botryomycosis may be found in the scalp, axilla, and groin and may involve underlying
muscles, tendons, and bones by direct extension.[973]