Papulosquamous disorders Notes


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Lichen planus

Pityriasis rosea


NOTES NOTES PAPULOSQUAMOUS DISORDERS GENERALLY, WHAT ARE THEY? PATHOLOGY & CAUSES ▪ Heterogeneous skin disorders; scaly papules, plaques ▫ Papule: circumscribed, solid elevation of skin < 1cm/0.39in ▫ Plaque: broad papule/confluence of papules ≥ 1cm/0.39in ▫ Scale: dry/greasy laminated masses of keratin CAUSES ▪ Inflammation SIGNS & SYMPTOMS ▪ See individual disorders DIAGNOSIS OTHER DIAGNOSTICS ▪ Rash patterns TREATMENT ▪ May spontaneously resolve MEDICATIONS ▪ Topical (e.g. corticosteroids), nonsteroidal anti-inflammatory drugs (NSAIDs), antihistamines ▪ Immunosuppressants, retinoids (e.g. acitretin) OTHER INTERVENTIONS ▪ Phototherapy, colloid baths LICHEN PLANUS PATHOLOGY & CAUSES ▪ Self-limiting chronic dermatosis ▪ Multifactorial pathogenesis ▫ Environmental factors → genetic aberrations of immune system ▫ CD8+ T cells respond to altered antigens in basal epidermidis/ dermoepidermal junction ▫ Causal agent identified: lichenoid reaction (e.g. drugs) 32 OSMOSIS.ORG ▪ Chronic inflammation in mucosal lesions → squamous cell carcinoma SIGNS & SYMPTOMS ▪ Shiny, flat-topped, pink-purple, polygonal papules coalesce, form plaques with red scales ▪ Wickham striae (pathognomonic) ▫ Interspersed grey-white lace-like pattern of lines
Chapter 6 Papulosquamous Disorders ▪ Symmetrical peripheral distribution, esp. on flexural surfaces (e.g. wrists, elbows, ankles, shins) ▪ Severe pruritus ▪ Koebner phenomenon ▫ Skin lesions induced by local trauma ▪ Nail involvement ▫ 10% of individuals; subungual thickening/hyperpigmentation, thinning/ ridging/ grooving of nail plate, pterygium formation, onycholysis ▪ Mucosal involvement ▪ Oral mucosa ▫ Asymptomatic/burning sensation,severe pain ▫ Mostly bilateral, inner cheeks ▫ Various types may coexist; oral variant of Wickham’s striae, erosive/ulcerative, papular, plaque-like, atrophic, bullous ▫ Possible secondary Candida infections ▪ Esophageal mucosa ▫ Dysphagia/odynophagia ▪ Genital mucosa (glans penis, vulva/vagina) ▫ Lower urinary tract symptoms, dyspareunia, itching in individuals who are biologically female MNEMONIC: 6 Ps ▫ Basal keratinocytes degenerate, appear like stratum spinosum cells (squamatization)/undergo necrosis, become incorporated into inflamed papillary dermis (Civatte bodies) OTHER DIAGNOSTICS ▪ Rash pattern distinctive at skin examination ▪ Skin biopsy ▫ Rule out secondary malignancies TREATMENT ▪ Cutaneous lesions spontaneously resolve in nine months, longer for mucosal lesions ▫ Leaves area of hyperpigmentation MEDICATIONS ▪ Reduce symptoms, shorten duration ▪ Antihistamines (pruritus), corticosteroids ▪ Retinoids, immunosuppressants OTHER INTERVENTIONS ▪ Occlusive dressings ▪ Phototherapy ▫ Ultraviolet A radiation Clinical presentation of lichen planus Planar Purple Polygonal Pruritic Papules Plaques DIAGNOSIS LAB RESULTS ▪ Typical microscopic features ▫ Acanthosis: epidermidis thickening ▫ Interface dermatitis: continuous infiltrate of lymphocytes along dermoepidermal junction → sawtoothing (dermoepidermal interface with zig-zag contour) Figure 6.1 Lesions on the shins of an individual with lichen planus. OSMOSIS.ORG 33
Figure 6.2 The histological appearance of lichen planus. There is a lymphocytic infiltrate at the junction between the dermis and epidermis which is known as interface dermatitis. PITYRIASIS ROSEA PATHOLOGY & CAUSES ▪ Self-limiting acute dermatosis ▪ Unknown etiology; may be viral in origin, related to human herpesvirus 7 (HHV7) SIGNS & SYMPTOMS ▪ Upper respiratory tract infection may precede rash ▪ “Herald patch” ▫ Solitary oval red plaque, usually located on trunk ▫ First skin lesion ▫ Spreads with central clearing, fading in 2–10 days ▪ 1–2 weeks after herald patch, multiple round/oval pink (white individuals of European descent)/dark brown (black individuals of sub-Saharan African descent) plaques with central scale appear 34 OSMOSIS.ORG ▪ Trunk, neck, upper arms, thighs; “Christmas tree” progression ▫ Across chest, then rib-line ▪ Pruritus ▪ Systemic ▫ Low-grade fever, headache, nausea, fatigue Figure 6.3 A herald patch is often seen at the onset of pityriasis rosea. It is a slightly raised, erythematous patch with superficial scaling.
Chapter 6 Papulosquamous Disorders DIAGNOSIS LAB RESULTS ▪ Skin biopsy (rare) ▪ Microscopic features ▫ Dyskeratosis: abnormal premature keratinization ▫ Extravasated erythrocytes within dermal papillae OTHER DIAGNOSTICS ▪ Rash pattern ▫ Distinctive at skin examination TREATMENT ▪ May spontaneously disappear in 6–8 weeks Figure 6.4 The clinical appearance of pityriasis rosea on the torso of an adult male. MEDICATIONS ▪ Antihistamines for pruritis OTHER INTERVENTIONS ▪ May spontaneously disappear in 6–8 weeks ▪ Colloid baths for pruritis PSORIASIS PATHOLOGY & CAUSES ▪ Chronic dermatosis of skin, nails, joints ▪ Multifactorial pathogenesis ▫ Environmental factors → genetic abnormalities of immune system ▫ CD4+ TH1, TH17, CD8+ T cells collect in epidermis, secrete cytokines (e.g. IFN-gamma, TNF-alpha, IL-17, IL22), growth factors → abnormal microenvironment (“cytokine soup”) accelerates keratinocyte proliferation → defective keratinization, epidermal thickening ▪ Unpredictable progression with spontaneous remissions, sudden exacerbations (e.g. may worsen in winter— lack of sun, humidity) ▫ Skin abrasion, infection, drugs (e.g. lithium, beta blockers, chloroquine), psychosocial stress → exacerbations ▪ 10–15% of individuals develop psoriatic arthritis ▫ Inflammatory cells in joint tissue → synoviocyte proliferation ▫ Surrounding connective tissue also involved (e.g. enthesitis) OSMOSIS.ORG 35
TYPES ▪ Plaque psoriasis, AKA vulgar psoriasis; 90% ▪ Guttate (eruptive), inverse (flexural), pustular, erythrodermic SIGNS & SYMPTOMS ▪ Plaque ▫ Pink, salmon-colored papules/plaques covered by loosely adherent silver-white scales ▫ Any area of body, esp. extensor surfaces (e.g. knees, elbows), lumbosacral area, scalp, glans penis ▫ Itching is mild/absent ▪ Nail involvement in 30% of individuals ▫ Subungual thickening ▫ Yellow-brown discolorations of nail plate (resembling oil slicks) ▫ Crumbling/ridging/pitting of nail plate ▫ Onycholysis: separation of nail plate from bed ▪ Guttate (eruptive) ▫ Drop-like appearance, associated with group A streptococcus ▪ Inverse (flexural) ▫ Skin folds ▪ Pustular ▫ Blisters filled with non-infectious pus ▪ Erythrodermic ▫ Total body inflammation, skin exfoliation, severe itching, swelling, pain; ability to regulate temperature, perform barrier functions impaired; possibly fatal ▫ May develop from any type (e.g. plaque during corticosteroid rebound phenomenon) ▪ Auspitz sign ▫ Pinpoint bleeding appears when scale removed ▪ Koebner phenomenon ▫ Characteristic skin lesions induced by local trauma ▪ Psoriatic arthritis ▫ Inflammatory arthritis: pain, red overlying area, swelling, hot to touch ▫ Frequently occurs after onset of rash ▫ Asymmetric peripheral oligoarthritis; 36 OSMOSIS.ORG joints of hands, feet most affected, followed by sacroiliac bone, spine ▫ Fusiform swelling of digits (dactylitis); aka “sausage digits” ▫ Aggressive disease with joint damage, malformations not common DIAGNOSIS DIAGNOSTIC IMAGING ▪ For psoriatic arthritis X-ray ▪ Erosive changes, “fluffy” periostitis, presence of new bone formation MRI ▪ Inflammation in adjacent bone marrow and soft tissues LAB RESULTS ▪ Skin biopsy (rare) ▪ Acanthosis ▫ Epidermidis thickening ▪ Parakeratosis ▫ Keratinization (retention of nuclei in stratum corneum) ▪ Neoangiogenesis with tortuous blood vessels below stratum corneum ▪ Accumulation of neutrophils in superficial epidermis (spongiform pustules), in stratum corneum (Munro microabscesses) ▪ Clinical diagnosis ▫ Psoriasis features, clinical pattern of joint involvement ▪ Confirmation ▫ Elevated inflammatory markers, negative rheumatoid factor (RF), anticyclic citrullinated peptide antibody (anti-CCP) OTHER DIAGNOSTICS ▪ Rash pattern ▫ Distinctive at skin examination ▪ Differentiation from rheumatoid arthritis ▫ Minority show polyarthritic pattern with no skin lesions; note asymmetry, distal interphalangeal joint involvement, mild joint destruction
Chapter 6 Papulosquamous Disorders TREATMENT ▪ No definitive cure ▪ Avoid triggers MEDICATIONS ▪ Topical corticosteroids → antiinflammatory, antiproliferative ▪ Vitamin D derivatives (calcipotriene, calcipotriol) → limit keratinocyte proliferation ▪ Anthralin → suppresses proliferation ▪ Combination therapy is most effective (e.g. betamethasone dipropionate + calcipotriene) ▪ Affected area > 10%, unsuccessful topical treatment, involves face, hands, genitals ▪ Immunosuppressant ▫ Methotrexate, cyclosporine ▪ Systemic retinoids ▫ Acitretin → inhibits pro-inflammatory cytokines ▪ Biologic therapy ▫ Anti-TNF (infliximab, etanercept, adalimumab), T-cells (alefacept), IL12/23 (ustekinumab) ▪ NSAIDs, immunosuppressant/biologic therapy ▫ For psoriatic arthritis Figure 6.5 A large psoriatic plaque on the upper limb. OTHER INTERVENTIONS ▪ Topical ▫ Coal tar → inhibits cellular mitotic activity, proliferation ▫ Moisturizers, emollients ▪ Phototherapy ▫ Ultraviolet A radiation ▫ Often combined with topical tar/ systemic acitretin/psoralen/methoxsalen ▫ Immunosuppressive, antiproliferative Figure 6.6 Psoriasis affecting the hand. OSMOSIS.ORG 37

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