It is also used for toxoplasmosis in people unable to tolerate trimethoprim with sulfamethoxazole.Dapsone by mouth was one of the first medications used to treat moderate to severe acne vulgaris, and is still occasionally prescribed for the treatment of severe cases. A topical form of dapsone is also effective with potentially less side effects.It is unclear if the combination with pyrimethamine is useful in the prevention of malaria. Autoimmune disease
Cutaneous lupus erythematosis. Dapsone is effective and safe in persons with moderate, severe, or refractory cutaneous lupus erythematosis. Idiopathic thrombocytopenic purpura. Dapsone is effective and safe for adjunctive glucocorticoid-sparing treatment of persons with idiopathic thrombocytopenic purpura and is preferred over danazol or interferon alpha in those people with antinuclear antibodies. Chronic spontaneous urticaria. Dapsone is effective and safe for treatment of second-line therapy for people with chronic spontaneous urticaria in those for whom antihistamines and other first-line agents have failed. Relapsing polychondritis. There are no clinical trials but there are many case reports that dapsone is effective at doses of 25 mg/day to 200 mg/day for treatment of relapsing polychondritis. Other
Dermatitis herpetiformis in combination with a gluten-free diet.Dapsone may be used to treat brown recluse spider bites that become necrotic.Dapsone is the recommended treatment for erythema elevatum diutinum, as a review found that using oral dapsone alone was effective in 80% of early cases of the disease.
For many years scientists attempted to develop a topical formulation of dapsone that would be as effective against acne as oral dapsone, but without the hemolysis side effect. This was difficult to accomplish because dapsone is highly insoluble in aqueous solvents. In the early 2000s QLT USA developed Aczone, a 5% dapsone gel that was shown to be effective against acne without causing clinically significant declines in hemoglobin levels, even in subjects with G6PD deficiency. In February 2016, the FDA approved a 7.5% dapsone gel. This higher strength has the advantage of a once-daily application, versus twice-daily application of the 5% formulation. Other uses
Dapsone also find uses as a curing agent in the manufacture of paints, adhesives, composites, powder coats, printed circuit boards, and imine-based vitrimers. See also
Promin, a more-soluble derivative

References
External links
"Dapsone". Drug Information Portal. U.S. National Library of Medicine.