What are the other Names for this Condition? (Also known as/Synonyms)

• PAC (Pyoderma Gangrenosum, Acne, and Ulcerative Colitis)
• PAC Syndrome
• PAU Syndrome

What is Pyoderma Gangrenosum, Acne, and Ulcerative Colitis? (Definition/Background Information)

• Pyoderma Gangrenosum, Acne, and Ulcerative Colitis (PAC) is a rare and severe inflammatory disorder that affects the skin, joints, and gastrointestinal tract. It is characterized by the presence of three conditions, namely pyoderma gangrenosum, severe acne, and ulcerative colitis
• The disorder may be caused by mutations in the PSTPIP1 gene (a few cases have been identified) and PAC is inherited in an autosomal dominant manner. Genetic and environmental factors may be contributory. The main risk factor for Pyoderma Gangrenosum, Acne, and Ulcerative Colitis is a positive family history of the disorder
• The signs and symptoms of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis include painful and rapidly progressing ulcerative lesions (pyoderma gangrenosum), acne conglobata with nodules and cysts (severe acne), and inflammation and ulceration of the colon and rectum (ulcerative colitis)
• The onset of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis may occur in adolescents or adults. The disorder is typically diagnosed based on the presence of the three conditions, a positive family history, a biopsy of the skin lesions, and genetic testing to confirm the presence of the PSTPIP1 gene mutation, if possible
• The treatment typically includes medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antibiotics, and immunosuppressive medications, to reduce inflammation and prevent recurrent episodes. Surgery may be required in case of severe ulcerative colitis
• The prognosis varies and depends on the severity of the disorder, one’s response to treatment, and the presence of any complications. With adequate treatment, most patients have an improved quality of life. A lack of treatment may lead to complications that include scarring, abdominal pain, perianal ulcers, and fistulas

PAC Syndrome is one of the six pyoderma gangrenosum-associated auto-inflammatory syndromes (PGAAIS) This family of diseases includes PAPA syndrome, PASH syndrome, PAPASH syndrome, PsAPASH syndrome, PASS syndrome, and PAC Syndrome.

Who gets Pyoderma Gangrenosum, Acne, and Ulcerative Colitis? (Age and Sex Distribution)

• Pyoderma Gangrenosum, Acne, and Ulcerative Colitis (PAC) is a rare disorder of unknown prevalence with onset in adolescence or early adulthood
• PAC Syndrome affects both males and females
• Worldwide, all racial and ethnic groups may be susceptible to the disorder

What are the Risk Factors for Pyoderma Gangrenosum, Acne, and Ulcerative Colitis? (Predisposing Factors)

The risk factors for Pyoderma Gangrenosum, Acne, and Ulcerative Colitis may include:

• Family history of the disorder
• Inheriting a copy of the mutated PSTPIP1 gene from a parent to develop the disorder

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis? (Etiology)

The cause of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis (PAC) is not fully understood, but it is believed to be a result of a combination of genetic and environmental factors.

• Mutations in the PSTPIP1 gene have been identified in some cases
• Abnormally high inflammation caused by a defective protein coded by the gene leads to the findings of PAC
• The disorder has an autosomal dominant pattern of inheritance

Autosomal dominant mode of inheritance: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly functioning gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition or pass it on to their offspring.

What are the Signs and Symptoms of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis?

The main signs and symptoms of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis (PAC) include:

• Painful and rapidly progressing skin ulcers (pyoderma gangrenosum)
• Nodules and cysts of severe acne that can occur on the face, neck, shoulders, chest, and back
• Inflammation and ulceration of the colon and rectum with food intolerance, nutritional malabsorption, and bloody diarrhea

Understanding each component disease will enhance understanding of PAC Syndrome and its consequences.

How is Pyoderma Gangrenosum, Acne, and Ulcerative Colitis Diagnosed?

Pyoderma Gangrenosum, Acne, and Ulcerative Colitis is diagnosed based on a combination of the following:

• Clinical examination and assessment of presenting signs and symptoms; the presence of the three distinct conditions is noted
• Evaluation of family history of the condition
• Medical testing that is necessary to diagnose each of the three conditions comprising the syndrome
• Cultures and biopsies of the skin lesions
• Genetic testing to confirm the presence of the PSTPIP1 gene mutation

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis?

Complications of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis can include:

• Bowel perforation, nutritional malabsorption, bloody diarrhea, and pain
• Chronic draining and painful skin ulcers
• Scarring due to acne
• Chronic non-healing skin ulcers of pyoderma gangrenosum
• Overall, decreased quality of life

How is Pyoderma Gangrenosum, Acne, and Ulcerative Colitis Treated?

Treatment for Pyoderma Gangrenosum, Acne, and Ulcerative Colitis typically includes medications, such as non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, antibiotics, and immunosuppressants, to reduce inflammation and prevent recurrent episodes.

• A regimen of anakinra daily, isotretinoin three times weekly, and prednisone every other day has been reported successful. Anakinra alone has been successful in one patient with less severe acne
• Surgery may be required in some cases to remove affected tissue of colitis unresponsive to medication

How can Pyoderma Gangrenosum, Acne, and Ulcerative Colitis be Prevented?

Presently, it is not possible to prevent Pyoderma Gangrenosum, Acne, and Ulcerative Colitis as the cause is a combination of genetic and environmental factors.

• Genetic counseling and testing may be recommended for individuals with a family history of the disorder and couples planning to have children
• However, early diagnosis and appropriate treatment can help manage the symptoms and prevent complications

What is the Prognosis of Pyoderma Gangrenosum, Acne, and Ulcerative Colitis? (Outcomes/Resolutions)

The prognosis for Pyoderma Gangrenosum, Acne, and Ulcerative Colitis varies and depends on the severity of the disorder, the individual’s response to treatment, and the presence of any complications. 

• With appropriate treatment, most individuals can have a good quality of life
• However, in the absence of treatment, the disorder can cause significant discomfort, pain, and decreased quality of life

Additional and Relevant Useful Information for Pyoderma Gangrenosum, Acne, and Ulcerative Colitis:

The following link is a useful resource for information on other rare conditions on DoveMed:

https://www.dovemed.com/diseases-conditions/rare-disorders/