Shedding a light on the importance of photopatch testing: A 12-year experience in a dermatology unit.

BACKGROUND: Photopatch testing has been standardized for diagnosing photoallergic contact dermatitis but is still infrequently used. OBJECTIVES: To characterize photopatch test (PPT) results and their clinical relevance. METHODS: We collected retrospective data from patients photopatch tested in our Dermatology Unit (2010-2021), using the European PPT 'baseline' series, other allergens, and patient's own products, when appropriate. RESULTS: Out of 223 patients, 75 patients (33.6%) were reactive with 124 positive PPT reactions, considered relevant in 56/223 patients (25.1%) and in 72/124 reactions (58.1%). Most reactions were caused by topical drugs (n = 33; 45.8%), such as ketoprofen or promethazine, and 7 (9.8%) by systemic drugs, such as hydrochlorothiazide and fenofibrate. 'Classical' ultraviolet filters were responsible for six positive PPT reactions whereas there was only three relevant PPT to the 'newer' UV filters. Patients' sunscreens/cosmetics or plant extracts caused 10 positive PPT each. Additional patch test reactions were observed, mostly to Tinosorb® M. CONCLUSION: Contrary to the trend in ACD, most positive PPT reactions were caused by topical drugs, outweighing ultraviolet filters and cosmetics. We stress the low reactivity to the 'newer' UV filters included in the PPT series. PPT was occasionally positive in systemic drug photosensitivity, but overall PPT reactivity was low.

Diffuse dermal angiomatosis: a rare cause of painful ulceration in renal insufficiency.

Diffuse dermal angiomatosis is a rare, benign, reactive cutaneous vascular proliferation that has been reported in the context of end-stage renal failure and can rarely be associated with arteriovenous fistulas. We report a striking clinical resolution following prompt diagnosis and subsequent arteriovenous fistula reversal. This case further demonstrates that accurate diagnosis is particularly rewarding since correct therapeutic approach can be curative.

Oligosecretory multiple myeloma: a devastating presentation of a difficult diagnosis.

A 57-year-old man with lumbar pain and fever was diagnosed with spondylodiscitis. Afterward, he acquired full paraplegia. Image studies showed a mass extending from D9 to the vertebral canal, plus numerous adjacent osteolytic lesions. Serum immunoelectrophoresis was normal, bone marrow had 0.5% of monoclonal plasmocytes, but D9's biopsy found a plasmacytoma. Despite bone marrow aspiration results, skeleton osteolytic lesions made multiple myeloma (MM) a more plausible diagnosis, later confirmed by the biopsy. The absence of classical MM findings, alongside a medullary compression syndrome, suggested an oligosecretory MM, which was proved by an altered FLC essay. This delayed diagnosis, with multiple diagnostic misguiding leads, also presents rare IgA and lambda chains production and normal levels of uninvolved immunoglobulins. Oligosecretory MM can lead to an inaccurate and delayed diagnosis, with devastating consequences to patient's morbidity and mortality. Therefore, FLC essay is essential in early assessment of potential MM patients.