Chapter 24: Skin Signs of Systemic Disease

INTRODUCTION TO CHAPTER

The skin, hair, and nails offer a window into the body. Many systemic conditions and diseases have major or distinct cutaneous manifestations. With practice, a complete skin examination can be rapidly conducted and provide information about underlying systemic disease.

CONNECTIVE TISSUES DISEASES

Discoid Lupus Erythematosus

Introduction

Discoid lupus erythematosus (DLE) is twice as common in women and is more common in African Americans. Conversion to systemic lupus erythematosus (SLE) is uncommon (5%), but in some cases discoid lupus-like lesions are the initial cutaneous sign of SLE.¹ Approximately 25% of patients with SLE will have discoid lupus lesions at some point in their disease.

Clinical Presentation

A. History and Physical Examination

The primary lesion is an angular, plaque with "follicular plugging," central atrophy and peripheral hyperpigmentation, and erythema (Figures 24-1 and 24-2).¹ Pruritus or burning are common symptoms. The lesions are primarily located on sun-exposed areas, generally the face, arms, scalp, upper chest, and back. Conchal fossa (bowl) scarring of the ear is almost pathognomonic (Figure 24-3). The scarring lesions of DLE may be disfiguring in patients with darker skin pigmentation, leaving permanent hypo- or hyperpigmentation. Scalp lesions may result in permanent hair loss due to scarring alopecia. Variants of DLE include hypertrophic, diffuse, and tumid, the latter two being less common.

B. Laboratory Findings

Antinuclear antibody (ANA), if present, is most often low titer. A skin biopsy of a lesion for direct immunofluorescence shows a positive lupus band (IgG, IgM, and C3 in a band-like pattern along the dermal-epidermal junction) in most patients.¹

Differential Diagnosis

• ✓ Seborrheic dermatitis, psoriasis, other photosensitive dermatoses, and tinea faciei.

Management

Mild to moderate limited disease can be treated with topical steroids or calcineurin inhibitors. Oral antimalarials such as hydroxychloroquine can be added for more widespread disease or disease that is disfiguring.² Methotrexate, prednisone, and other systemic immunomodulators are other options for systemic therapy. Sunscreens, hats, and sun protective clothing should be regularly used.

Subacute Cutaneous Lupus Erythematosus

Introduction

Subacute ...