This indicates that the reaction is only a characteristic of the patients with solar urticaria and that it is not phototoxic. It is possible that this photoallergen is located on the binding sites of IgE that are found on the surface of mast cells. The photoallergen is believed to begin its configuration through the absorption of radiation by a chromophore. The molecule, because of the radiation, is transformed resulting in the formation of a new photoallergen. Diagnosis
Solar urticaria can be difficult to diagnose, but its presence can be confirmed by the process of phototesting. There are several forms of these tests including photopatch tests, phototests, photoprovocation tests, and laboratory tests. All of these are necessary to determine the exact condition of the patient. Photopatch tests are patch tests conducted when it is believed that a patient is experiencing certain symptoms due to an allergy that will only occur when in contact with sunlight. After the procedure, the patient is given a low dosage of UVA radiation. Another test known as a phototest is the most useful in identifying solar urticaria. In this test, one centimeter segments of skin are subject to varying amounts of UVA and UVB radiation in order to determine the specific dosage of the certain form of radiation that causes the urticaria to form.
Mogamulizumab, sold under the brand name Poteligeo, is a humanized, afucosylated monoclonal antibody targeting CC chemokine receptor 4 (CCR4). The  U.S. Food and Drug Administration (FDA) approved it in August 2018 for treatment of relapsed or refractory mycosis fungoides and Sézary disease. It was approved in Japan in 2012, for the treatment of relapsed or refractory CCR4+ adult T-cell leukemia/lymphoma (ATCLL) and in 2014, for relapsed or refractory CCR4+ cutaneous T cell lymphoma (CTCL). The latter approval was based on study with 28 subjects.The precursor to mogamulizumab was a mouse anti-human CCR4 IgG1 mAb (KM2160), that was made in 1996 in a collaboration between Kouji Matsushima of University of Tokyo and Kyowa Hakko Kirin. Kyowa humanized it, and expressed the humanized gene in a CHO cell line in which FUT8 had been knocked out, which produced antibodies with no fucose in the Fc region. This is thought to enhance its antibody-dependent cell-mediated cytotoxicity. It was first tested in humans in 2007.Kyowa licensed rights for use outside of cancer to Amgen in 2008, for $100 million up front and $420 million in biodollars. Amgen ran a Phase I study to explore its use in asthma. Amgen terminated the agreement in 2014.As of 2014, there were reports that mogamulizimab can cause serious skin rashes and some cases of Stevens–Johnson syndrome.In 2017, the US FDA granted it a priority review for CTCL. Full approval was granted in August 2018. The U.S. Food and Drug Administration (FDA) considers it to be a first-in-class medication.