<unk>  is a systemic, immune-mediated disease that is characterized by inflammation of the skin and joints. It commonly causes erythematous scaly patches on the skin. The scaly patches caused by<unk> , called<unk> oriatic plaques, are areas of inflammation and excessive skin production. Skin rapidly accumulates at these sites and takes on a silvery-white appearance. Plaques frequently occur on the skin of the elbows and knees, but can affect any area including the scalp and genitals.<unk>  is hypothesized to be immune-mediated and is not contagious.<unk>  is a chronic recurring condition which varies in severity from minor localized patches to complete body coverage. Fingernails and toenails are frequently affected, which is referred to as<unk> oriatic nail dystrophy.<unk>  can also cause inflammation of the joints, which is known as<unk> oriatic arthritis. 10-15% of people with<unk>  have<unk> oriatic arthritis. The International<unk>  Council identifies four main forms of<unk> : plaque-type<unk> , guttate<unk> , generalized pustular<unk>  (GPP), and erythrodermic<unk> . The pathophysiology of<unk>  consists of interactions between cytokines, dendritic cells, and T lymphocytes (particularly Th1 and Th17).<unk>  must be differentiated from other diseases that cause an erythematous, scaly rash such as cutaneous T cell lymphoma/mycosis fungoides, pityriasis rosea, pityriasis rubra pilaris, pityriasis lichenoides chronica, nummular dermatitis, secondary syphilis, Bowen’s disease, exanthematous pustulosis, hypertrophic lichen planus, Sneddon–Wilkinson disease, small plaque parapsoriasis, intertrigo, Langerhans cell histiocytosis, dyshidrotic dermatitis, tinea manuum/pedum/capitis, and seborrheic dermatitis. The prevalence of<unk>  is estimated to be between 500 and 4,600 cases annually per 100,000 people. The mainstay of therapy for<unk>  is topical agents applied directly onto the lesions. Topical agents include corticosteroids, vitamin D analogues, tar, anthralin, tazarotene, calcineurin inhibitors, and aloe vera extracts. Systemic therapy may also be used; this can include immunosupressants to counteract the progression of the disease.
Psoriasis
Parapsoriasis
Lupus vulgaris
Vitiligo
Sycosis vulgaris
Acne vulgaris
Alopecia mucinosa
Nummular dermatitis