Azathioprine hypersensitivity presenting as a neutrophilic dermatosis in a man with ulcerative colitis.

We report a case of a 46-year-old man with ulcerative colitis being treated with oral prednisolone and azathioprine. Two weeks after the initiation of azathioprine he presented with fever, fatigue, myalgias and arthralgias and a painful cutaneous eruption that was most marked in a sun-exposed distribution. This was accompanied by loose, non-bloody diarrhoea. Histopathological assessment of a skin biopsy supported a diagnosis of a neutrophilic dermatosis. The azathioprine was temporarily withheld and oral prednisolone was increased as it was thought that the neutrophilic dermatosis was associated with the underlying ulcerative colitis. The patient's symptoms and cutaneous eruption resolved quickly and azathioprine was re-introduced. Within 24 h, systemic symptoms returned along with a florid recrudescence of his cutaneous eruption. This rapidly improved upon withdrawal of azathioprine.

Oral nicotinamide protects against ultraviolet radiation-induced immunosuppression in humans.

Cutaneous immunity, which is a key defence against the development of skin cancers, is suppressed by even small doses of ultraviolet (UV) radiation. Preventing this UV-induced immunosuppression may therefore reduce the incidence of skin cancer. Nicotinamide (vitamin B3) has immune-protective and cancer-preventive effects against UV radiation in mice, and we have shown previously that topical nicotinamide is immune protective in humans. Using the Mantoux model of skin immunity in healthy volunteers, we compared oral nicotinamide to placebo (both administered for 1 week) in a randomized, double-blinded, crossover design against the effects of solar-simulated ultraviolet (ssUV) radiation on delayed-type hypersensitivity to tuberculin purified protein derivative. Discrete areas of the back were irradiated with low doses of ssUV daily for three consecutive days. Immunosuppression, calculated as the difference in Mantoux-induced erythema of irradiated sites compared with unirradiated control sites, was determined in volunteers taking oral nicotinamide and placebo. Significant immunosuppression occurred in an UV dose-dependent manner in the presence of placebo. Oral nicotinamide, at doses of either 1500 or 500 mg daily, was well tolerated and significantly reduced UV immunosuppression with no immune effects in unirradiated skin. Oral nicotinamide is safe and inexpensive and looks promising as a chemopreventive supplement for reducing the immunosuppressive effects of sunlight.

A comparative study between transmission electron microscopy and immunofluorescence mapping in the diagnosis of epidermolysis bullosa.

The classification of epidermolysis bullosa (EB) into 3 main subtypes has been based on transmission electron microscopy (TEM) that is able to directly visualize and quantify specific ultrastructural features. Immunofluorescence antigenic mapping (IFM) is a technique that determines the precise level of skin cleavage by determining binding sites for a series of antibodies. To date, no study has compared the accuracy of these two techniques in diagnosing the major types of EB. A prospective cohort of 33 patients thought to have EB on clinical grounds had TEM, IFM, and genetic testing performed. The sensitivities and specificities of TEM and IFM were calculated compared with the genetic results. Of 33 cases, 30 had a positive EB diagnosis. TEM subclassified EB into its three major forms in 24/30 cases (80%) and IFM in 29/30 cases (97%). Overall, TEM sensitivities and specificities when compared with genetic results were 71% and 81%, respectively. IFM sensitivities and specificities when compared with genetic results were 97% and 100%, respectively. If a patient tested positive for EB by IFM, the likelihood ratio of having a particular type of EB was consistently greater than 20 against the reference standard (compared with a likelihood ratio less than 10 for TEM). Our results indicate that the diagnosis of EB is improved (sometimes substantially) by the use of IFM compared with TEM.