Most FDA approved agents speak to acne vulgaris, in general, on their approved labelled indications. Nodular severe acne may not be a specifically approved indication but would be included under more general labeling for acne.
Light and laser therapies administered by clinical professionals have also been developed and approved.
Retinoids, antibiotics and benzoyl peroxide are all mentioned as the mainstay for therapy. While hormonal therapy is discussed in the medical community, acne is not a labelled indication.
While the FDA is one source for good information on specific drugs and devices, the American Academy of Dermatology has clinical guidelines that may help determine what shows evidence of working — and also guide as to what may not work or potentially be harmful.