Infectious Disease

A 40-year-old womanwith HIV infection has had an occasionallypruritic facial rash for severalmonths. The rash is not associatedwith any systemic symptoms.

A 46-year-old man with diabetes presented for evaluation of gradual fingernail deterioration, which had failed to respond to several courses of griseofulvin and a recent 3-month course of daily terbinafine. The patient-who worked as a bartender-was otherwise healthy.

For several weeks, a 78-year-old woman had an intensely pruritic, diffuse, raised, slightly scaly, erythematous rash that persisted despite the use of several over-the-counter topical medications (such as hydrocortisone and clotrimazole cream). Since her last visit about 3 months earlier for a blood pressure reading, she had been well except for 2 episodes of night sweats.

Sorting through the myriad of causes of soft tissue infections can be a daunting diagnostic challenge. While much is written about empiric treatment of skin and soft tissue infections, it is important to make a correct diagnosis, since clinical findings in common versus exotic and mild versus life-threatening infections have significant overlap. Historical information, such as the temporal progression of signs and symptoms, travel history, animal exposure, age, occupation, bite history, underlying diseases, and lifestyle, is important in focusing the differential diagnosis toward specific causes. Still, clinical assessment is frequently not sufficient and laboratory tests, radiographic imaging, and surgical intervention may be necessary to establish a specific diagnosis and to provide the rationale for definitive management.

A 52-year-old man complains of nausea, fever, and malaise following a 2-day diarrhealillness that developed at the end of a family vacation in New England.Two family members suffered a similar illness, characterized by watery diarrhea.Symptoms developed in all who were affected within 24 hours of eatinghamburgers at a local restaurant.

A 70-year-old man who had just completeda course of trimethoprim-sulfamethoxazolefor a urinary tract infectionpresented with palpable purpuraand cutaneous erosions of acute onseton his legs (A). He also had massivescrotal edema and purpura (B).

ABSTRACT: Because physical findings are an unreliable indicator of deep venous thrombosis (DVT), the diagnosis is based on the presence of clinical risk factors and the results of noninvasive tests, such as duplex ultrasonography and impedance plethysmography. Contrast venography is considered the gold standard for the diagnosis of DVT. Uncomplicated DVT is managed with low molecular weight heparin followed by warfarin. When DVT is complicated (eg, by pregnancy or by evidence of pulmonary embolism), the patient is treated with intravenous heparin; the dosage is adjusted to achieve an activated partial thromboplastin time 3 times control. Chronic venous insufficiency is the most common cause of leg ulcers. Treatment goals include reduction of edema, relief of pain, ulcer healing, and prevention of recurrence. Leg elevation and multilayer elastic compression dressings are the mainstays of therapy. Compression dressings are continued until ulcers heal; graded compression stockings are worn to prevent recurrence. Pentoxifylline, 400 mg 3 times a day, is an effective adjunct to compression bandaging. Large or slow-healing ulcers may require skin grafts.

During the past week, a rash on theright thumb and forefinger of a 4-yearoldboy has progressed to involve theentire arm.

A palpable papulosquamous, arciform chronic eruptionhad been present in a 70-year-old man for many years.The asymptomatic rash was in a “mantle” distribution-across the upper shoulders, neck, and back.

Large, reddish tan, asymptomatic patches recently developedon the trunk of a 36-year-old man. Five years earlier,a similar outbreak had resolved after a 10-day course oforal ketoconazole; this episode was the first recurrence.

For several months, a 19-year-old manhad asymptomatic hyperpigmentedand hypopigmented macules on theright volar forearm. Recent applicationsof topical corticosteroids madethe lesions more noticeable.

Extreme synovial inflammation resulted in the articular degradation seen in the hands of this 40-year-old woman who has Still disease, or juvenile rheumatoid arthritis (JRA).

ABSTRACT: The basic screening studies for rheumatic diseases are a complete blood cell count, a determination of the erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) level, a rheumatoid factor assay, an antinuclear antibody (ANA) test, a measurement of serum uric acid level, and a urinalysis. Test results must be interpreted within a clinical context; for example, a positive ANA assay suggests the possibility of a rheumatic disorder, but it is not specific for any diagnosis. Tests that reveal the nature and extent of target-organ involvement, such as renal function studies in patients with systemic lupus erythematosus, can help guide the selection of therapy. Laboratory results also reflect disease activity; the ESR and CRP level are useful gauges of the activity of most inflammatory rheumatic disorders. Finally, laboratory monitoring can help you minimize the significant toxicity associated with many of the drugs used to manage rheumatic diseases.

A52-year-old white man presented with a pruritic eruption on the neck of 3 months’ duration. The rash had not responded to a potent topical corticosteroid prescribed by another practitioner for the presumed diagnosis of eczema. The patient reported no current health problems. His history included a pubic louse infestation and several episodes of uncomplicated urethral gonorrhea. He readily admitted to having unprotected sexual intercourse with prostitutes.

A 24-year-old man presented for evaluation of pruritic vesicles on both feet.Ten days earlier, dyshidrotic eczema had been diagnosed by another physicianwho prescribed triamcinolone ointment. The patient reported that the footeruption worsened after the topical medication was applied.

A 70-year-old man first noticed thisskin condition when he returned fromthe South Pacific at the end of WorldWar II. Over the years, the rash hasitched only occasionally; however,during a recent spate of hot weather,the eruption became highly pruritic.Applications of an over-the-counter1% hydrocortisone ointment exacerbatedthe condition

An eruption on the face of a 49-year-old woman had been misdiagnosed as astaphylococcal infection; the rash failed to respond to oral and topical antibiotics.A mid-potency topical corticosteroid also had been tried, but the eruptionworsened.

The parents of a 3-year-old girl sought evaluation of their daughter’s hair loss.During the past several months, a large patch of alopecia with scaling had developed.The differential diagnosis included seborrhea, trichotillomania, andtinea capitis.

A new lesion recently arose on the right flexor forearm ofa 67-year-old man. The 1-cm, pruritic, pink, circular, slightlyraised lesion was perfectly homogeneous with no centralclearing.

A 49-year-old man was concerned about a right flexor forearmlesion that had been increasing in size for 6 weeks.The light pink, well-demarcated, 5-cm, circular lesion featuredslight peripheral elevation with ulceration, crusting,and a relatively clear central area. A culture of materialfrom the lesion was negative for fungi. A potassium hydroxideevaluation was not performed.

A 56-year-old man had an asymmetric,maculopapular, sharply demarcated,pruritic, excoriated dermatitis on hisupper thighs. The eruption had beenpresent for 2 to 3 weeks

For about 4 months, a very dry, diffuse,fine scaly, asymptomatic eruptioncovered the palms of a 28-yearoldman; several fingernails weredystrophic bilaterally as well. Beforethe onset of this condition, bilateralonychomycosis of the toenails hadbeen diagnosed. The toenails had notbeen treated and were still affectedat the time of presentation. Branchinghyphae were seen on a potassiumhydroxide preparation of a fingernailcutting. The patient had tinea manuumand tinea unguium

Numerous factors contribute to the medication errors that kill up to 98,000 patients each year. Unnecessarily high dosages can result in increased side effects with only a small therapeutic benefit, especially in elderly patients. Lack of patient information-such as a history of allergies or adverse drug reactions-is another cause of error and injury. Communication failures include the use of ambiguous abbreviations, misinterpretation of verbal orders, and lack of timely response to a patient's medication-related symptoms. Dosing errors are common in children because of variability in dosage expressions in drug references. Remedies for prescribing errors are described in detail here.

A methodical approach to diagnosis usually reveals the cause of fever. In patients with simple fever, a careful history taking and physical examination combined with basic laboratory and imaging studies (complete blood cell count with differential, urinalysis, and possibly a chest film and blood cultures) usually yield the diagnosis. In patients with prolonged fever whose cause remains undiagnosed after extensive examination (fever of unknown origin), repeat the history taking and physical examination; also order routine laboratory studies, an HIV test, a tuberculin skin test, 3 sets of blood cultures, and chest films. In addition, abdominal CT scanning is often useful. Further testing at this point may include fluorodeoxyglucose positron emission tomography, technetium-tagged white blood cell scanning, transesophageal echocardiography, liver biopsy, bone marrow examination, and/or temporal artery biopsy. Exploratory laparotomy is rarely indicated.

Tinea infections can be diag- nosed by potassium hydroxide (KOH) examination, which reveals fungal elements when a preparation of scale from a lesion-particularly the active border-is studied under a microscope; culture; and histopathologic examination of a skin biopsy specimen or nail clippings with periodic acid–Schiff stain. Culture may be warranted when a fungal infection is strongly suspected despite a negative KOH result. Unfortunately, dermatophyte cultures can take from 4 to 6 weeks to become positive; therefore, treatment decisions may have to be made before culture findings are reported. A topical antifungal is the initial therapy for tinea cruris, tinea corporis, tinea pedis, and tinea manuum. Tinea capitis, extensive tinea corporis, and tinea unguium are best treated initially with oral antifungal agents, because these infections usually do not respond to topical therapy.