Rash and Arthritis

Henry Lee

Rachelle Scott

Animesh A. Sinha

KEY POINTS

Mucocutaneous lesions are an important clinical feature of a number of conditions presenting with arthritis, ranging from infectious to autoimmune etiologies.
Detailed cutaneous examination, including an examination of nail folds, genitalia, and oral mucosa, may aid in the proper diagnosis.
Description of mucocutaneous lesions should include the color, shape, and morphology of the primary lesion, the pattern in which the lesion occurs, and its distribution.
Biopsy of the lesion may aid in proper diagnosis. Immunofluorescent (IF) studies and tissue culture should be analyzed in appropriate cases.

INTRODUCTION

The differential diagnosis and approach to arthritis and rash are complex. Cutaneous lesions may provide insights into the underlying disease and diagnosis.
Mucocutaneous lesions may precede other systemic symptoms and may herald the onset of a multisystemic disease process. The diagnosis of several rheumatologic conditions relies on dermatologic manifestations as part of the diagnostic criteria, reinforcing the importance of a thorough cutaneous examination. In Table 16-1, we discuss some of the basic terminology of the morphology and the description of cutaneous lesions. In Table 16-2, we categorize the diseases that commonly present with both arthritis and rash according to their etiologies. This chapter follows the organization set in Table 16-2.

Although many of the diseases are protean and overlap in their presentations, in Table 16-3 we outline a basic guide to some of the primary lesions that may aid the physician in arriving at the proper diagnosis. The goal of this chapter is to provide the physician with diagnostic information about specific cutaneous findings in each disorder and to offer insights to these multisystemic conditions through the perspective of a dermatologist.

Table 16-1 Fundamental Dermatologic Descriptive Terminology

Term	Definition
Macule	A flat area of color change that is nonpalpable, <1 cm in diameter
Patch	A large macule <1 cm in diameter
Papule	A solid elevation, palpable with no visible fluid, <1 cm in diameter
Plaque	A large papule <1 cm in diameter
Nodule	A palpable, solid, round, or ellipsoidal lesion; depth of lesion and/or palpability may differentiate it from papule
Wheal	An evanescent, edematous, and flat-topped elevation of various sizes; no surface change, as the epidermis is unaffected
Vesicle	A circumscribed elevation that, unlike papules, contains fluid, <1 cm in diameter
Bulla	A large vesicle >1 cm in diameter
Pustule	An elevation similar to vesicles that contains purulent material (composed of leukocytes, ±cellular debris, ±bacteria)
Scale	An accumulation of stratum corneum; can vary in color and texture
Crust	Dried serum, pus, or blood resulting in hardened debris ±epithelial cells, ±bacterial debris
Excoriation	An abrasion produced by mechanical means
Fissure	A linear cleft through the epidermis with variable involvement of dermis
Erosion	Loss of all or portion of epidermis; if only epidermis is involved, there is no scar
Ulcer	An excavation that has lost its epidermis and some of its dermis. Will form scars with healing (dermis involvement)
Telangiectasia	Dilated, small vascular lesion that blanches with pressure
Atrophy	Thinning of skin that may affect any level of skin; loss of skin surface texture and structures ±translucency
Petechia	An intradermal hemorrhage that is nonpalpable <3 mm in diameter
Purpura	A large petechia that is <3mm in diameter
Poikiloderma	Triad of atrophy, telangiectasia, and pigmentary change (hyper- or hypopigmented)
Alopecia	Loss of hair; usually categorized as scarring vs. nonscarring

Table 16-2 Diseases that Manifest with Both Cutaneous and Joint Complaints

Spondyloarthropathy
1. Reactive arthritis
2. Psoriatic arthritis
3. Inflammatory bowel disease
Lupus erythematosus
Dermatomyositis/polymyositis
Systemic scleroderma–mixed connective tissue disorder
Sjögren’s syndrome
Rheumatoid arthritis
Juvenile idiopathic arthritis
Vasculitis
1. Small-sized vessel vasculitis (e.g., LCV, HSP, mixed cryoglobulinemia, and UV)
2. Medium-sized vessel vasculitis (e.g., PAN)
3. ANCA-positive vasculitides (e.g., WG, CS, and MPA)
Behçet’s disease
Sarcoidosis
Multicentric reticulohistiocytosis
Relapsing polychondritis
Acne fulminans
Sweet’s syndrome
Pyodermic gangrenosum
Erythema nodosum
Infections
1. Viral (e.g., parvovirus B19, rubella, varicella-zoster, and hepatitis B/C)
2. Bacterial (e.g., disseminated gonorrhea infection, acute meningococcemia, syphilis, Lyme disease, and mycobacterium)
3. Fungal (e.g., sporotrichosis, candida, histoplasmosis, coccidioidomycosis, and cryptococcosis)
4. Rheumatic fever–postinfectious condition

ANCA, antineutrophil cytoplasmic antibodies; CS, Churg-Strauss; HSP, Henoch-Schönlein purpura; LCV, leukocytoclastic vasculitis; MPA, microscopic polyangiitis; PAN, polyarteritis nodosa; UV, urticarial vasculitis; WG, Wegener’s granulomatosis.

DISEASE STATES

I. Spondyloarthropathies

(see Chapter 39) refer to a family of disorders that share a predilection for spinal and sacroiliac joint inflammation and enthesitis. Mucocutaneous findings are prominent in three of these disorders.

Reactive arthritis (see Chapter 42) was originally described as a triad of arthritis, conjunctivitis, and nongonococcal urethritis. Many have expanded this triad to a tetrad to include mucocutaneous lesions.

Balanitis circinata are moist superficial ulcers on the glans or corona of the penis and may coalesce to give a circinate appearance. They are reported to occur in approximately 36% of patients. Erosion, erythema, and asymptomatic superficial ulcers may be seen in the mouth and pharynx.

Keratoderma blennorrhagica are hyperkeratotic papules and plaques usually found on the palms and soles. These lesions begin as clear vesicles on an erythematous base and cannot be clinically differentiated from pustular psoriasis. The less specific findings of psoriasiform dermatitis and erythroderma can be found in a subset of patients.

Table 16-3 Characteristic Cutaneous Morphologies of Selected Conditions Presenting with Arthritis and Skin Findings

Erythematous papules/plaques
Psoriasis
SCLE
DLE
Gottron’s papules
Sarcoid-lupus pernio
Secondary syphillis
Sweet’s syndrome “relief of mountain range”
Lyme-ECM
Secondary syphilis
Disseminated gonorrhea infection
Erythematous-violaceous patches
ACLE (i.e., malar rash)
DM-heliotrope rash (more violaceous)
DM–shawl sign
Parvovirus–slapped cheek
Lyme-ECM
Rheumatic fever–erythema marginatum
Annular plaques
SCLE
DLE
Sarcoid
Psoriasis
Ulcers
Reactive arthritis
Behçet’s disease
Pyoderma gangrenosum
Vasculitis
Sarcoidosis
Nodules
Erythema nodosum
Lupus profundus
Rheumatic fever nodules
Vasculitis
Sarcoidosis
Hyperkeratotic palms/soles
Reactive arthritis/Reiter’s (keratoderma blennorrhagica)
Palmoplantar psoriasis
Palpable purpura
Vasculitis (i.e., LCV)
Erythematous macules
JIA—generalized erythematous macules
Rubella
Calcinosis cutis
DM
Sclerodermas

Please note that this is a simplified categorization. Many of the above entities may present in a number of manifestations.
ACLE, acute cutaneous lupus erythematosus; DLE, discoid lupus erythematosus; DM, dermatomyositis; ECM, erythema chronicum migrans; JIA, juvenile idiopathic arthritis; LCV, leukocytoclastic vasculitis; SCLE, subacute cutaneous lupus erythematosus.

Nail changes include erythema of the nail fold, subungual hyperkeratotic deposits, onychodystrophy (abnormal growth of nails), and a yellowish discoloration of the nails.
Treatment of simple mucocutaneous lesions. Topical corticosteroids and topical keratolytics (i.e., 20% salicylic ointment) if necessary.

Psoriatic arthritis (see Chapter 41) is broadly defined as an inflammatory arthritis associated with the cutaneous findings of psoriasis. These patients are often rheumatoid factor (RF) negative. The arthritis exhibits a more limited involvement of the spine, when compared to other types of spondyloarthropathy, and exhibits more peripheral involvement of the joints.
- Cutaneous lesions usually precede arthritic complaints.
- Classic psoriasis vulgaris cutaneous lesions are described as well-demarcated erythematous plaques with nonadherent scale that are commonly found on elbows, knees, scalp, and lumbosacral region.
- Inverse psoriasis localizes to intertriginous area (usually no scale).
- Guttate psoriasis presents as small teardrop-shaped psoriatic lesions.
- Pustular psoriasis presents as sterile pustules that may coalesce to form “lakes of pus.” It may be accompanied by fever and leukocytosis.
- Palmoplantar psoriasis presents as pustules on soles and palms that progress to scaly, erythematous patches/plaques.
- Erythroderma presents as thickened, erythematous, and scaly skin.
- Nail changes can be associated with any form of psoriasis. These changes are seen in 80% of psoriatic arthritis and only 30% of pure cutaneous psoriasis. Nail findings include “oil spots” (yellow–brown spots), nail pits, onycholysis, and onychodystrophy.
- Auspitz sign is the removal of scale, which leads to punctate blood drop.
- Köbner phenomenon is the appearance of new lesions at sites of trauma.
- Medications that may cause a flare include β-blockers, lithium, and chloroquine. Withdrawal of systemic steroids may cause a flare.
- Topical treatments for rash include topical corticosteroids and vitamin D₃ analogs (i.e., calcipotriol). They are often used together.
- Systemic treatments include psoralen plus ultraviolet A (UVA), narrow band ultraviolet B (UVB), retinoids, methotrexate, cyclosporine, and biologic agents (i.e., etanercept, infliximab, adalimumab, efalizumab, and alefacept). The use of systemic steroid leads to transient improvement but patients may experience withdrawal flare.
Inflammatory bowel disease (IBD)–related spondyloarthropathy (see Chapter 40)
- Erythema nodosum (EN) occurs in approximately 7% or less of patients with ulcerative colitis.
- Pyoderma gangrenosum (see section XII of this chapter) occurs in approximately 1% of patients with Crohn’s disease and approximately 5% of patients with ulcerative colitis.
- Patients may also exhibit aphthous ulcers and nutritional deficiencies.

II. SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

(see Chapter 30).

Acute cutaneous lupus erythematosus (ACLE) includes malar rash but can occur elsewhere on the body. Malar or “butterfly” rash presents as an erythema that covers the cheeks and nose (may extend onto forehead and chin). Lesions are often exacerbated by sunlight (see Table 16-4A for a differential diagnosis).
Subacute cutaneous lupus erythematosus (SCLE) lesions are papulosquamous or annular plaques. The papulosquamous plaques are confluent and discrete erythematous papules and plaques with scales. The annular plaques often coalesce into larger plaques, forming polycyclic shapes. The borders remain erythematous but the central areas exhibit subtle hypopigmentation and telangiectasia. These lesions are nonscarring and predominantly affect white women (see Table 16-4B for a differential diagnosis).
- High frequency of anti-Ro antibodies is observed in patients with SCLE (approximately 70% of patients).
- Approximately 50% of patients meet the SLE criteria but only 10% will develop severe disease.
Chronic cutaneous lupus erythematosus (CCLE) lesions include a variety of lesions, of which discoid lupus is the most prevalent.

Discoid lupus erythematosus (DLE) lesions are well-demarcated erythematous plaques with scale. As lesions mature, they may develop central atrophy. Keratinous plugging of hair follicles can be seen as tiny spikes across the lesion. Lesions are often found on the face, scalp, neck, and ears. Lesions may cause scarring. Approximately 5% of patients will go on to develop SLE (see Table 16-4C for a differential diagnosis).

Table 16-4A Differential Diagnosis of the Malar Rash of Acute Cutaneous Lupus Erythematosus

Dermatomyositis
Parvovirus
Photoallergic/phototoxic reaction
Seborrheic dermatitis
Acne rosacea
Polymorphous light eruption

Table 16-4B Differential Diagnosis of Subacute Cutaneous Lupus Erythematosus

Psoriasis
Dermatomyositis
Nummular eczema
Polymorphous light eruption
Contact dermatitis
Dermatophyte infection (i.e., Tinea corporis)
Cutaneous T-cell lymphoma

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