Bone abnormalities can be seen on radiological imaging (often increased density or osteosclerosis) or  biopsy.There are two sets of diagnostic criteria, the Lipsker criteria published in 2001 and the Strasbourg criteria that were produced at a meeting in that city in 2012.The Lipsker criteria require hives, the presence of monoclonal IgM, and at least 2 of the following: fever, joint pain or arthritis, bone pain, swollen lymph nodes, enlarged spleen or liver, elevated erythrocyte sedimentation rate, high levels of white blood cells, and findings of problems in bone imaging.In the Strasbourg criteria, the person must have hives and the presence of monoclonal IgM or IgG. Schnitzlers is diagnosed if the person has IgM and two of the following, or IgG and three of the following: recurrent fevers, abnormalities in bone imaging, with or without bone pain, findings of neutrophil infiltration in a skin biopsy, high levels of white blood cells or C-reactive protein.Other conditions which can cause periodic fevers, paraproteins or chronic hives that should be ruled out, include (and are not limited to) autoimmune or autoinflammatory disorders such as adult-onset Stills disease, angioedema, hematological disorders such as lymphoma or monoclonal gammopathy of undetermined significance (MGUS), other causes of hives, cryoglobulinemia, mastocytosis, chronic neonatal onset multisystem inflammatory disease or Muckle–Wells syndrome. Treatment
As of 2017 no drug was approved to treat Schnitzlers. Drugs that inhibit interleukin 1 activity have been the preferred treatment since they emerged in 2005; since 2012 a consensus guideline has recommended treatment with anakinra.
Sarcoidosis, an inflammatory disease,  involves the skin in about 25% of patients. The most common lesions are erythema nodosum, plaques, maculopapular eruptions, subcutaneous nodules, and lupus pernio. Treatment is not required, since the lesions usually resolve spontaneously in two to four weeks. Although it may be disfiguring, cutaneous sarcoidosis rarely causes major problems. Classification
Morphology
Ulcerative sarcoidosis is a cutaneous condition affecting roughly 5% of people with sarcoidosis. : 710 Annular sarcoidosis is a cutaneous condition characterized by papular skin lesions arranged in annular
patterns, usually with a red-brown hue. : 709

Pattern
Morpheaform sarcoidosis is a very rare cutaneous condition characterized by specific cutaneous skin lesions of sarcoidosis accompanied by substantial fibrosis, simulating morphea. : 711 Erythrodermic sarcoidosis is a cutaneous condition and very rare form of sarcoidosis. : 710 Hypopigmented sarcoidosis is a cutaneous condition characterized by areas of hypopigmented skin. It is usually diagnosed in darkly pigmented races and may be the earliest sign of sarcoidosis. : 709 Papular sarcoid is a cutaneous condition characterized by papules, which are the most common morphology of cutaneous sarcoidosis. : 708 Ichthyosiform sarcoidosis is a cutaneous condition resembling ichthyosis vulgaris or acquired ichthyosis, with fine scaling usually on the distal extremities, by caused by sarcoidosis. : 710

Location
Subcutaneous sarcoidosis (also known as "Darier–Roussy disease" and "Darier-Roussy sarcoid") is a cutaneous condition characterized by numerous 0.5- to 0.3-cm deep-seated nodules on the trunk and extremities. : 710 Scar sarcoid (also known as "Sarcoidosis in scars") is a cutaneous condition characterized by infiltration and elevation of tattoos and old flat scars due to sarcoidosis.