Studies on treatment patterns of psoriasis are valuable to evaluate how efficiently psoriasis patients are treated and facilitate improved outcomes for these patients. In the Nurses' Health Study II which includes data for 116,430 female nurses, 2107 women reported to have a diagnosis of psoriasis made by a medical provider. Psoriasis Screening Tool-2 (PST-2) was sent to all of these women. PST-2 is a validated diagnostic tool for psoriasis, which also queries participants for age at disease diagnosis, treatments, type of psoriasis lesions, body surface area involved, and the provider who made the diagnosis. Among 2107 participants, 1338 completed and retuned the survey, with 1243 of them validated for having psoriasis. The average age at diagnosis was 47 years (standard deviation:15 years). 79% of the patients reported mild, 17% moderate and 4% severe disease. 41% of the patients reported plaque lesions, 22% nail, 49% scalp, 15% palmoplantar and 27% inverse psoriasis. In people with mild psoriasis, 67% were diagnosed by dermatologists and 33% by non-dermatologist providers. In those with moderate-to-severe psoriasis, 87% were diagnosed by dermatologists. In people with mild psoriasis, 58% received only topical medication, 5% only systemic, 5% systemic and topical, 4% topical and phototherapy, and 26% received no treatment. In people with moderate-to-severe psoriasis, 42% received only topical medication, 17% systemic and topical, 12% systemic, topical and phototherapy, 11% topical and phototherapy, and 11% received no treatment. Among traditional systemic therapies, methotrexate and among targeted systemic therapies adalimumab were the most commonly used medications. In conclusion, high percentage of psoriasis patients are being diagnosed and managed by non-dermatologist providers which demonstrates the importance of engaging them in educational initiative on disease treatment. Significant numbers of people with moderate-tosevere disease are undertreated.