Papulosquamous Dermatoses

Info

🌱 來自: Huppert’s Notes

Papulosquamous Dermatoses🚧 施工中

Papulosquamous Dermatoses

Psoriasis

•   Pathophysiology: Immune dysregulation (Th1, Th17, excess IFN-gamma) and keratinocyte hyperproliferation

•   Clinical features: Thick, well-demarcated salmon-colored plaques with overlying silvery scale; classically on the extensor surfaces (e.g., knees, elbows) but can also be seen on the scalp, palms/feet (palmoplantar psoriasis), nails (pitting, “oil spots”) and flexural areas (inverse psoriasis); lesions will bleed if picked (Auspitz sign); 30% of patients have concurrent psoriatic arthritis; associated with metabolic syndrome and greater risk of cardiovascular disease

•   Treatment: Depends on disease severity

-   Limited: Topical glucocorticoids, topical vitamin D analogues (calcipotriene, calcitriol), and/or topical retinoids (tazotarotene)

-   Moderate/Severe: Phototherapy, methotrexate (+folate), cyclosporine, apremilast, or biologics

•   Anti-TNF: Adalimumab (Humira), etanercept (Enbrel), infliximab (Remicade)

•   Anti-IL-12/23: Ustekinumab (Stelara)

•   Anti-IL-17: Secukinumab (Cosentyx)

Lichen planus

•   Pathophysiology: T-cell-mediated

•   Clinical features: 4Ps: Pruritic, Polygonal, Purple, Papules, most commonly on the ankles, wrists, and membranes; associated with HCV infection

•   Treatment: Topical glucocorticoids (mild disease) or systemic steroids, oral retinoids, sulfasalazine, hydroxychloroquine, or phototherapy (severe disease)

Pityriasis rosea

•   Pathophysiology: Immune reaction to viral infection or reactivation (e.g., HHV6/7) or less commonly drug-induced pityriasis rosea

•   Clinical features: Begins as a red, oval plaque with fine scale (“herald patch”), followed 1–20 days later by numerous similar lesions on the chest and back (“Christmas tree” distribution); typically follows relaxed skin tension lines; does not involve the face, scalp, palms or soles

•   Treatment: Time (spontaneously resolves in 6–12 wks) and good skin care (moisturize, gentle soaps); can use topical glucocorticoids (may reduce the itch while waiting for the rash to resolve)

•   Pearls: 1) Herald patch is absent in 50% of cases, 2) Consider ruling out syphilis (has a similar appearance)

Seborrheic dermatitis

•   Pathophysiology: Associated with Malassezia furfur

•   Clinical features: Greasy yellow and erythematous scaly patches on the scalp, central face (nose, eyebrows), ears, axillae, chest, and inguinal folds; “cradle cap” in kids, “dandruff” in adults

•   Treatment: Selenium sulfide or zinc pyrithione shampoo, ketoconazole cream or shampoo, weak or low-potency topical glucocorticoids if severely inflamed

•   Pearl: If severe/refractory seborrheic dermatitis, test for HIV (severity correlates with CD4 count)