Acne fulminans (acute febrile ulcerative acne) seems to be immunologically induced systemic disease, in which the offending antigen is P.acnes [immediate complex and delayed (types III and IV) hypersensitivity reactions].
The patients are predominantly young males who quite suddenly develop extensive inflammatory lesions (oozing friable plaques with haemorrhagic crusts) especially on the trunk. The often ulcerated lesions can lead to significant scarring. The affected patients often have typical mild to moderate acne prior to the onset of acne fulminans.
Many associated features have been reported e.g. fever, polyarthropathy, bone pain (aseptic osteolysis), painful splenomegaly, erythema nodosum, marked leukocytosis, anorexia and general malaise. Blood cultures are universally sterile. The prognosis for bone lesions is good, and chronic sequelae, if any, are mild, leading to mild sclerosis and hyperostosis.
Testosterone treatment, anabolic steroids (some athletes abuse them), and oral isotretinoin may induce acne fulminans. One case has been reported in a young man with late-onset congenital adrenal hyperplasia. An acne fulminans-like picture has been reported in association with Epstein–Barr virus infection. Thus, patients with a sudden exacerbation of previously relatively mild acne should be checked for infectious mononucleosis.
Oral prednisolone therapy is required urgently with other medications such as salicylates/ non-steroidal anti-inflammatory drugs and oral antibiotics. Oral low dose isotretinoin is cautiously introduced after about 4 weeks of oral prednisolone and gradually increased as tolerated, according to clinical response and the daily dose of prednisolone is slowly decreased as tolerated.
Topically crusts are removed by soaking the skin with emollient oil followed by the use of a potent steroid/antiseptic cream for 2 to 3 weeks; occasionally with intralesional steroid.
It should be noted that oral isotretinoin itself in general can initially induce inflammatory flares of acne, occasionally leading to acne fulminans as stated above and mild flares do not require modification of the oral dose and improve spontaneously but severe episodes should be treated with systemic corticosteroids, and dose reduction or discontinuation of isotretinoin may be required.
Isotretinoin in combination with dapsone has been used successfully to treat acne fulminans associated with erythema nodosum.
Few patients develop severe vasculitic pyoderma gangrenosum-like lesions (vasculitic acne).
SAPHO syndrome is manifested by synovitis, acne, pustulosis, hyperostosis, and osteitis. It is predominantly associated with hyperostosis of the anterior chest, palmoplantar pustulosis, hidradenitis suppurativa, and acne fulminans.
An autosomal dominant disorder of pyogenic sterile arthritis, pyoderma gangrenosum and severe acne (PAPA syndrome) was described in 1997.