Psoriasis Vulgaris Diagnosis and Treatment

Diagnosis

Psoriasis vulgaris is a chronic inflammatory skin disease that classically presents with well-demarcated, red plaques with silvery scale, commonly involving the scalp, elbows, knees, and presacral region, according to the American Academy of Dermatology and National Psoriasis Foundation guidelines 1
The clinical presentation of well-demarcated plaques with silvery scale on the elbows that bleed when picked (Auspitz sign) is diagnostic of psoriasis vulgaris, which is primarily a clinical diagnosis that does not require laboratory testing for rheumatoid factor or ESR 1
Psoriasis vulgaris can be classified based on the percentage of Body Surface Area (BSA) affected:

Topical corticosteroids, medium to high potency (Class II-III), such as betamethasone dipropionate 0.05% or fluocinonide 0.05%, are recommended by the American Academy of Dermatology for elbow plaques, applied once or twice daily for 2-4 weeks, then tapered to intermittent use, with caution to avoid prolonged use due to risk of skin atrophy 2
Vitamin D analogs + topical corticosteroids, such as calcipotriene/betamethasone dipropionate combination, have superior efficacy compared to either agent alone, applied once daily for up to 4 weeks, then maintenance therapy, as suggested by the American Academy of Dermatology 1
Methotrexate (7.5-25mg weekly) is recommended by the American Academy of Dermatology as a first-line systemic therapy for moderate-to-severe disease 3

Common locations for psoriasis include the scalp (approximately 50% of patients), elbows, knees, presacral region, trunk, and intertriginous areas, with special areas like the face, genitals, hands, feet, nails, and intertriginous regions often causing disproportionate physical and emotional distress despite affecting smaller surface areas 4, 5, 2
Psoriasis severity is not solely determined by body surface area, as location matters significantly, and even when affecting less than 5% of body surface area, psoriasis in special locations can be considered severe 5
Treatment pitfalls to avoid include undertreatment of seemingly "mild" disease, overuse of high-potency topical steroids leading to skin atrophy, and failure to address psychological impact of visible skin disease, as noted by the American Academy of Dermatology 2
Intertriginous areas require careful steroid use due to atrophy risk 4
Other forms of psoriasis include guttate psoriasis, pustular psoriasis, and erythrodermic psoriasis, each with distinct characteristics and locations 4