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Amicrobial pustulosis of the folds
Other Resources UpToDate PubMed

Amicrobial pustulosis of the folds

Contributors: Lauren Mihailides MD, Lisa Cotter MD, Susan Burgin MD
Other Resources UpToDate PubMed


Amicrobial pustulosis of the folds (APF), also known as amicrobial pustulosis associated with autoimmune disease (APAD), is a rare neutrophilic dermatosis. APF usually occurs in young women and most often is associated with an underlying autoimmune condition. Associated diseases include systemic lupus erythematosus, immune thrombocytopenic purpura, Sjögren syndrome, Hashimoto thyroiditis, and rheumatoid arthritis, among others.

The pustules in APF are sterile, but the lesions can become eroded and secondarily infected. Diagnosis of APF is based largely on clinical presentation and exclusion of other more common diagnoses.

The disease is generally chronic with frequent relapses despite treatment. The disease course of APF does not parallel that of any associated autoimmune disease.


D89.89 – Other specified disorders involving the immune mechanism, not elsewhere classified

95329006 – Autoimmune skin disease

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Differential Diagnosis & Pitfalls

Patient history, distribution, negative bacterial and fungal cultures, and negative direct immunofluorescence (DIF) help in the diagnosis of APF.

Other pustular rashes:
  • Candidiasis
  • Acute generalized exanthematous pustulosis
  • Inverse psoriasis – pustules are not sterile
  • Pustular psoriasis – more generalized, often with history of psoriasis and steroid use
  • Generalized pustular psoriasis
  • Impetigo herpetiformis
  • Subcorneal pustular dermatosis (Sneddon-Wilkinson disease)
  • IgA pemphigus
  • Pemphigus foliaceus

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Last Reviewed:02/06/2017
Last Updated:03/05/2023
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Amicrobial pustulosis of the folds
A medical illustration showing key findings of Amicrobial pustulosis of the folds : Scalp
Copyright © 2024 VisualDx®. All rights reserved.