Psoriasis

Diagnosis: Psoriasis

Submitted by Dr. Shahbaz A. Janjua to dermRounds Dermatology Network

Clinical Presentation

Psoriasis Submitted by Dr. Shahbaz A. Janjua to dermRounds Dermatology Network

Clinical History

Well-defined erythematous plaques with silvery-white scale. Common sites: scalp, elbows, knees, lumbosacral, nails. Family history. Screen for psoriatic arthritis and metabolic syndrome.

Treatment

Mild: topical corticosteroids, vitamin D analogues, calcineurin inhibitors. Moderate: phototherapy (NB-UVB). Severe: methotrexate, cyclosporine, apremilast, biologics (TNF, IL-17, IL-23 inhibitors). Combination topical therapy.

Differential Diagnosis

• Eczema/atopic dermatitis • Seborrheic dermatitis • Lichen planus • Pityriasis rosea • Tinea corporis • Secondary syphilis • Mycosis fungoides • Nummular eczema

Key Learnings

• Immune-mediated disease driven by Th17/IL-23 axis • Auspitz sign: pinpoint bleeding when scale is removed (dilated capillaries in dermal papillae) • Koebner phenomenon: lesions develop at sites of trauma • Nail involvement in ~50%: pitting, oil drop sign, onycholysis, subungual hyperkeratosis • Psoriatic arthritis develops in ~30% — screen regularly (CASPAR criteria) • Metabolic syndrome, cardiovascular disease, and depression are major comorbidities • Biologic therapy has revolutionized treatment — IL-17 and IL-23 inhibitors achieve PASI 90/100 in many patients • Histology: regular acanthosis, Munro microabscesses, dilated capillaries in dermal papillae, diminished granular layer

Tags: dermatologist, dermatology, dermrounds