Viral exanthem (Chapter 27) | All ages and both sexes. More common in children. Less common than drug exanthems in hospital setting. Exposure in community and autoactivation are important factors | Abrupt onset with gradual worsening. Variable pruritus. Dependent on underlying virus but typically associated fever, cough, sore throat, myalgias, headache, lymphadenopathy, conjunctivitis, nausea, vomiting, and diarrhea | Maculopapular, morbilliform, urticarial, and vesicular lesions. Often mucosal lesions. Consider: HIV, EBV, CMV, HHV-6, HHV-7, rubella, rubeola, enteroviruses, adenoviruses, parvovirus B-19, and varicella. (All figures in Chapter 27.) Varies depending on specific causative virus | CBC with atypical lymphs, lymphopenia or lymphocytosis; LFTs, viral specific antibody tests; nasopharyngeal, throat, stool washings, and swabs |
Herpes simplex (HSV) Herpes zoster (VZV) (Chapter 11) | All ages, races, and both sexes. Worldwide. VZV more common in >age 50. Severe, recurrent HSV and VZV in immunosuppressed patients | Tingling, pain, and burning sensation may precede rash. VZV is dermatomal with possible dissemination. Rare cutaneous dissemination of HSV in atopics | Grouped vesicles and crusting on red base (Figure 11-1). HSV usually recurrent in the same place. VZV is dermatomal (Figure 11-3). Severe, widespread, ulcerating disease in immunosuppressed | Tzanck smear of lesion. DFA, PCR, and viral culture |
Cellulitis (Chapter 12) | All ages, races, and both sexes. More common with trauma, portals, and broken skin | Abrupt onset of tenderness and pain with variable chills, malaise, and fever | Sudden appearance of tender, red, warm, edematous ill-defined or sharply demarcated advancing erythema, generally unilateral (Figure 12-3)10 | CBC with leukocytosis and left shift. Cultures from definite portal may be helpful. Biopsy for tissue cultures if unresponsive to treatment or immunosuppressed |
Pyoderma (abscess) (Chapter 12) | All ages, races, and both sexes. More common with trauma, portals, and broken skin | Acute or subacute onset of variably tender or pruritic areas of skin | Pyoderma with weeping, eroded, crusted, purulent lesions with surrounding erythema (Figure 12-1). Abscesses with tender fluctuant red nodules with or without surrounding erythema (Figure 12-2) | Skin culture after incision for abscess |
Candidiasis (Chapter 10) | All ages, races, and both sexes. Risk factors: broad-spectrum antibiotics, diabetes, hyperhidrosis, occlusion, and corticosteroid use | Acute or subacute. Pruritus, tenderness, and burning | Bright red moist or erosive dermatitis, poorly marginated with satellite and lesional pustules in intertriginous areas (Figure 10-16), genitals, scrotum, and areas of occlusion (Figure 10-17). Mucous membranes with white removable exudates on red patches (Figure 38-22) | KOH with budding yeast and pseudohyphae. Cultures recommended if unresponsive to treatment |
Fungal infection (Chapter 10) | All races and both sexes. T. capitis prepubertal, all other forms commonly postpubertal. M > F for T. cruris and T. pedis. Severity and extent can be worse in immunosuppressed. Relative risk factors: obesity, hyperhidrosis, age, and occlusion. Tinea is an important cause of broken skin and portals for bacterial infection (cellulitis) | Generally subacute or chronic with exacerbations | Generally dry and scaling. On body (Figure 10-4) and groin (Figure 10-7) with annular configuration and central clearing/active border. Spares scrotum. On feet, possibly moccasin (Figure 10-10) or interdigital distribution (Figure 10-9). Rarer inflammatory with vesicopustules (Figure 10-11). Nails with powdery scale and subungual debris (Figure 10-12) | KOH with branching hyphal structures. PAS stain of nail or skin will demonstrate the same. Fungal culture to identify species |