The Bottom Line

Acne fulminans is a rare dermatologic emergency—it comes on suddenly with explosive, painful nodules and ulcers, usually on the chest and back, along with fever and joint pain. It affects mostly teenage boys and young men. Without fast treatment (typically hospitalization, steroids, antibiotics, and isotretinoin), it causes severe permanent scarring. If acne appears suddenly with open ulcers and you feel systemically unwell, seek medical care right away.

What Is Acne Fulminans?

Acne fulminans is one of the most severe and rare forms of acne. It is different from typical acne in how fast it develops and how sick it makes you feel. While most acne builds up gradually, acne fulminans erupts explosively over days to weeks—large, painful nodules and cysts rapidly turn into open ulcers with purulent (pus-filled) drainage and bloody crusts. At the same time, patients often develop fever, joint pain, and profound fatigue.

The condition is rare, affecting just 0.1–0.4% of acne patients. It has a striking 8–10:1 male-to-female ratio and peaks between the ages of 15 and 25. About 50–60% of patients meet criteria for "acne fulminans syndrome" because of the systemic symptoms. In 10–20% of cases, it can be triggered by starting isotretinoin (Accutane) at a high initial dose.

Signs and Symptoms

The hallmark of acne fulminans is an explosive sudden onset. Skin findings include:

  • Large (1–5 cm), severely painful nodules and cysts, mostly on the chest, back, shoulders, and sometimes the face
  • Rapid progression from papules to nodules to open, draining ulcers over just 1–2 weeks
  • Hemorrhagic (bloody) crusts and purulent drainage
  • Extensive scarring begins forming almost immediately

Systemic (whole-body) symptoms occur in 50–60% of patients and include:

  • High fever (38–40°C / 100–104°F)
  • Severe joint pain, most commonly in the knees and hips
  • Fatigue, weight loss, and muscle aches
  • Elevated inflammatory markers on blood tests (CRP, white blood cell count)
  • Elevated liver enzymes in 30–40% of cases

What Causes Acne Fulminans?

Acne fulminans is thought to result from a severe immune overreaction to bacteria that live on the skin (Cutibacterium acnes), driven by several factors:

  • An exaggerated immune response that causes massive inflammation, including activation of the complement system
  • High androgen (male hormone) levels that drive extreme oil gland activity
  • A genetic predisposition—60–70% of patients carry specific HLA immune system markers (HLA-B12, HLA-B44), and most have a strong family history of severe acne
  • In some cases, starting isotretinoin at too high an initial dose triggers the condition

Treatment Options

Acne fulminans is a medical emergency. Most patients require hospitalization. Treatment is aggressive and multi-step:

  • Hospitalization and IV antibiotics: Intravenous antibiotics (cefazolin or clindamycin) are given for 2–4 weeks to cover skin bacteria. Oral antibiotics continue for an additional 4–6 weeks afterward. Total antibiotic course is 8–10 weeks.
  • Systemic corticosteroids (prednisone): This is the first priority—to suppress the overwhelming immune response. Prednisone is started at 0.5–1 mg/kg/day and tapered gradually over 8–12 weeks. In very severe cases, high-dose IV methylprednisolone is given first. Improvement is typically seen within 1–2 weeks.
  • Isotretinoin: Essential for long-term control and preventing relapse. However, it must be started carefully—only after 4–6 weeks of steroids have calmed the inflammation. Starting isotretinoin too early or at too high a dose can paradoxically worsen acne fulminans. Your dermatologist will start at a low dose and increase gradually.
  • Wound care: Open ulcers require careful wound care to prevent secondary infection and minimize scarring.
  • Scar management: After active disease is fully controlled, procedures like laser resurfacing can address the scarring left behind.

When to See a Dermatologist

  • You develop severe, sudden-onset acne with painful ulcers over days to weeks
  • Your acne is accompanied by fever, joint pain, or feeling very unwell
  • You are currently taking isotretinoin and your acne suddenly gets dramatically worse
  • You develop open, draining sores on your chest or back
  • Standard acne treatments are not working and your skin is worsening rapidly
  • You have a strong family history of very severe acne and your own acne is escalating quickly

Frequently Asked Questions

Can isotretinoin cause acne fulminans?

In 10–20% of cases, yes. Starting isotretinoin at too high an initial dose can trigger acne fulminans in susceptible individuals—particularly teenage boys with severe pre-existing acne. This is one reason dermatologists start isotretinoin at a low dose and sometimes add a short course of prednisone at the beginning in high-risk patients. If you are on isotretinoin and your skin explodes with painful ulcers or you develop fever and joint pain, contact your dermatologist or go to the emergency room immediately.

How is acne fulminans different from severe regular acne?

The key differences are speed of onset (days vs. months), the presence of open ulcers and systemic symptoms (fever, joint pain), and the extreme severity and rapid scarring. Regular severe cystic acne—even acne conglobata—develops more slowly and usually does not cause fever or joint pain.

Will the scarring be permanent?

Without fast, aggressive treatment, yes—severe permanent scarring is common. This is why acne fulminans is considered an emergency. The faster treatment begins, the better the outcome. After the disease is fully controlled, scar revision procedures can improve the appearance of existing scars, but prevention through early treatment is critical.

Is acne fulminans contagious?

No. Acne fulminans is not caused by a contagious infection. While bacteria on the skin (Cutibacterium acnes) play a role, the real driver is a genetic predisposition to an extreme immune reaction. You cannot catch it from another person.

References

  1. Karvonen SL. Acne fulminans: report of clinical findings and treatment of twenty-four patients. J Am Acad Dermatol. 1993;28(4):572-579.
  2. Greywal T, et al. Evidence-based recommendations for the management of acne fulminans and its variants. J Am Acad Dermatol. 2017;77(1):109-117.
  3. Dessinioti C, Katsambas A. Difficult and rare forms of acne. Clin Dermatol. 2017;35(2):138-146.
  4. Jansen T, Plewig G. Acne fulminans. Int J Dermatol. 1998;37(4):254-257.

Trusted Resources

Always consult a board-certified dermatologist for diagnosis and personalized treatment recommendations.