Chapter 053. Eczema and Dermatitis (Part 10) pptx

Table 53-5 Common Skin Infections Clinical Features Etiologic Agent Treatmen t Impetigo Honey-colored crusted papules, plaques, or bullae Group A Streptococcus and Staphylococcus aur

Chapter 053 Eczema and

Dermatitis (Part 10)

Ecthyma is a variant of impetigo that causes punched-out ulcerative lesions

It may result from neglected or inadequately treated impetigo Treatment of both ecthyma and impetigo involves gentle debridement of adherent crusts, which is facilitated by the use of soaks and topical antibiotics, in conjunction with

appropriate oral antibiotics Furunculosis is also caused by S aureus, and this

disorder has gained prominence in the last decade because of CA-MRSA A furuncle, or boil, is a painful, erythematous, nodule that can occur on any cutaneous surface The lesions may be solitary but are most often multiple Patients frequently believe they have been bitten by spiders or insects Family members or close contacts may also be affected Furuncles can rupture and drain spontaneously or may need incision and drainage, which may be adequate therapy

for small solitary furuncles without cellulitis or systemic symptoms Whenever possible, lesional material should be sent for culture Current recommendations for methicillin-sensitive infections are β-lactam antibiotics Therapy for CA-MRSA was discussed previously (see "Atopic Dermatitis") Warm compresses and nasal mupirocin are helpful therapeutic additions Severe infections may require IV antibiotics

Table 53-5 Common Skin Infections

Clinical Features

Etiologic Agent

Treatmen

t

Impetigo Honey-colored

crusted papules, plaques, or bullae

Group A

Streptococcus and Staphylococcus aureus

Systemic

or topical antistaphylococc

al antibiotics

Dermatophytos

is

Inflammatory

or noninflammatory annular scaly plaques;

may have hair loss;

groin involvement

Trichophyto

n, Epidermophyton,

or Microsporum

Topical azoles, systemic griseofulvin, terbinafine, or

spares scrotum;

hyphae on KOH preparation

Candidiasis Inflammatory

papules and plaques with satellite pustules, frequently in intertriginous areas;

may involve scrotum;

pseudohyphae on KOH preparation

Candida albicans and other Candida species

Topical nystatin or azoles; systemic azoles for resistant disease

Tinea

versicolor

Hyperpigment

ed or hypopigmented scaly patches on the trunk; characteristic mixture of hyphae and spores on KOH preparation

("spaghetti and

Malassezia furfur

Topical selenium sulfide lotion or azoles

meatballs")

Erysipelas and Cellulitis

See Chap 119

Dermatophytosis

Dermatophytes are fungi that infect skin, hair, and nails and include

members of the genera Trichophyton, Microsporum, and Epidermophyton Tinea

corporis, or infection of the relatively hairless skin of the body (glabrous skin), may have a variable appearance depending on the extent of the associated inflammatory reaction (see Fig 52-11) Typical infections have an annular appearance that patients refer to as "ringworm." Deep inflammatory nodules or granulomas occur in some infections—especially in those infections inappropriately treated with mid- to high-potency topical glucocorticoids Involvement of the groin (tinea cruris) is more common in males than females It presents as a scaling, erythematous eruption sparing the scrotum Infection of the foot (tinea pedis) is the most common dermatophyte infection and is often chronic;

it is characterized by variable erythema, edema, scaling, pruritus, and occasionally vesiculation Involvement may be widespread or localized but generally involves the web space between the fourth and fifth toes Infection of the nails (tinea unguium or onychomycosis) occurs in many patients with tinea pedis and is

characterized by opacified, thickened nails and subungual debris The distal-lateral variant is most common Proximal subungual onychomycosis may be a marker for HIV infection or other immunocompromised states Dermatophyte infection of the scalp (tinea capitis) has returned in epidemic proportions, particularly affecting

inner-city children, but it also affects adults The predominant organism is T tonsurans, which can produce a relatively noninflammatory infection with mild scale and hair loss that is diffuse or localized T tonsurans can also cause a

markedly inflammatory dermatosis with edema and nodules This latter presentation is a kerion

The diagnosis of tinea can be made from skin scrapings, nail scrapings, or hair by culture or direct microscopic examination with potassium hydroxide (KOH) Nail clippings may be sent for histologic examination with periodic acid Schiff (PAS) stain