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Chapter 42: Skin Diseases Involving Multiple Body Regions

Brittney Schultz; Noah Goldfarb

INTRODUCTION

Many common diseases such as atopic dermatitis, psoriasis, drug rashes, urticaria, viral exanthems, bug bites, and vitiligo present with lesions in multiple body regions. Less common disorders such as syphilis, erythema multiforme, Stevens–Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), immunobullous diseases, cutaneous T-cell lymphomas, and connective tissue disorders also present in multiple body locations. The presence or absence of mucosal involvement can be a helpful clue.

APPROACH TO DIAGNOSIS

Skin diseases involving multiple body sites can be broadly placed into the following categories starting with the most common (Table 42-1):

  • Inflammatory Dermatoses

  • Infectious Diseases

  • Infestations and bites

  • Drug rashes and urticaria

  • Connective tissue diseases

  • Autoimmune bullous diseases

  • Pigment disorders

  • Neoplastic

Table 42-1.Differential diagnosis of skin diseases involving multiple body regions.
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Table 42-1. Differential diagnosis of skin diseases involving multiple body regions.
Disease Epidemiology, History, and Physical Examination
Inflammatory Dermatoses

Allergic contact dermatitis

image

Epidemiology:

 Common.

 F > M.

 Age: Any age, may be more common in adults due to increased product usage.

History:

 Pruritus.

 Onset is hours to days after contact with allergen.

Physical Exam:

 Geometric or linear configuration as well as a sharply demarcated distribution are clues to an external cause.

Acute: Pink to red, edematous papules and plaques with vesiculation.

Chronic: Xerosis, fissuring, hyperpigmentation, and lichenification at sites of direct contact with allergen.

Typical Locations: Scalp, face, eyelids, earlobes, neck, hands, wrists, or feet.

Distribution can be a clue to culprit allergen.

Distinguish from other types of dermatitis due to a sharply demarcated distribution and geometric/linear configuration. Patch testing required to distinguish allergic from irritant contact dermatitis. Distinguish from atopic dermatitis due to history of atopy and additional classic areas of involvement of atopic dermatitis.

(see Chapter 8).

Irritant contact dermatitis

image

Epidemiology:

 Common.

 F > M.

 Age: Any age.

History:

 Pruritic, painful, or burning. May have history of atopy.

 Variable onset depending on frequency of exposure and strength of irritant.

 More common in occupations that require frequent hand washing and exposure to water/soap such as health care workers, janitorial services, and food industry employees.

 Patients with atopic dermatitis are at increased risk.

Physical Exam:

 Well-demarcated plaque with a "glazed" appearance.

 Typical Locations: Eyelids, hands, forearms, and face.

 May appear identical to allergic contact dermatitis. Need patch testing to differentiate.

 (see Chapter 8).

Atopic dermatitis (AD)

image

Epidemiology:

 Common.

 F > M.

 Age: Can occur at any age, but most commonly occurs in infancy and childhood. Adult onset can occur.

History:

 Pruritus. Chronic course with exacerbations.

 Superinfection common.

 Usually worse in winter. Personal and family history of atopy (asthma, seasonal allergies, allergic rhinitis, atopic dermatitis).

Physical Exam:

 Red papules, scaly plaques, lichenification, and excoriations.

 Typical Locations:

 Infants: Cheeks, trunk, and extensor extremities.

 Children & Adults: Neck, wrists, hands, ankles, feet, and flexor extremities, especially antecubital and popliteal fossae.

 Distinguish from psoriasis based on ...

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