Amicrobial intertriginous pustulose L98.2

Oberlin et al. 1991

Very rare, localized, chronically recurrent, neutrophilic (pustular) dermatosis that manifests mainly in the large flexures of the axillae, the groin and possibly also perianally as well as on the digital acras or capillitium. After a longer period of persistence, extensive erosive plaques develop.

Associated autoimmune diseases have been described as:

• systemic lupus erythematosus
• antiphospholipid syndrome
• Crohn's disease
• Hashimoto's thyroiditis (Wang MZ et al. 2017).

Furthermore, an association with IgA nephropathy and a Sjögren's syndrome has been described.

w:m=9:1; very rare; <100 cases have been reported so far (Schissler C et al. 2017)

Large joint flexures (axillary, inguinal), capillitium, external auditory canals, anogenital, navel. Less common is infestation of the oral mucosa (DD: pyostomatitis vegetans).

In young women, development of a localized, therapy-resistant, sterile pustulosis in the area of the large joint flexures. After prolonged persistence, erosive weeping red plaques develop. The clinical appearance changes with the localization (auditory canal: erosive otitis externa), capillitium (pustular, weeping dermatitis), digital acra (purulent paronychia with consecutive onychodystrophy).

Spongiotic dermatitis with formation of (sterile) pustules and an inflammatory infiltrate of neutrophil granulocytes, lymphocytes and macrophages extending into the mid-corium. Discrete signs of vasculitis. In 30% of cases evidence of a lupus band at the dermo-epidermal junction (?).

Immunosuppressive (glucocorticoids, cyclosporin A); still successful in individual cases: Anakinra; TNF-alpha-blocker.

1. Bellinato F et al (2020) Amicrobial pustulosis of the folds: report of three new cases. Indian J Dermatol 65:323-324.
2. López-Navarro N et al (2009) Amicrobial pustulosis of the folds associated with Hashimoto's thyroiditis. Clin Exp Dermatol 34:e561-563.
3. Marzano AV et al (2008) Amicrobial pustulosis of the folds. Report of 6 cases and a literature review. Dermatology 216:305-311
4. Natsuga K et al (2007) Amicrobial pustulosis associated with IgA nephropathy and Sjögren's syndrome. J Am Acad Dermatol 57:523-526.
5. Oberlin P et al (1991) Pustulosis amicrobienne et lupus eythemateux systemique. Ann Dermatol Venereol 118: 824-825.
6. Saint-Jean M et al (2011) Amicrobial pustulosis of the skin folds and autoimmune erythroblastopenia. Ann Dermatol Venereol 138:399-404
7. Schissler C et al (2017) Amicrobial pustulosis of the folds: Where have we gone 25years after its original description? Ann Dermatol Venereol 144:169 175.
8. Wang MZ et al (2017) Amicrobial pustulosis of the folds: report of 4 cases. J Cutan Pathol 44:367-372.