Laboratory Studies
In erosive pustulosis of the scalp, direct immunofluorescence studies on biopsy tissue may be considered to rule out immunobullous disorders. Results are typically negative in persons with erosive pustulosis of the scalp. A case of erosive pustulosis of the leg has shown discontinuous immunoglobulin M and C3 deposition in the basement membrane and some dermal blood vessels. [19]
Bacterial, acid-fast bacilli, and fungal cultures of purulent material and/or tissue should also be considered. While the pustules of erosive pustulosis of the scalp should be sterile, superinfection of the overlying crust may lead to false-positive culture results.
Imaging Studies
Erosive pustulosis of the scalp is a clinical diagnosis. No imaging is necessary.
Procedures
A skin biopsy should be considered to exclude carcinoma, since it may be difficult to distinguish squamous cell carcinoma from erosive pustular dermatosis of the scalp.
Histologic Findings
Histopathologic findings in erosive pustulosis of the scalp are nonspecific. Parakeratotic and orthokeratotic scales may be noted in association with atrophy, erosion, loss of hair follicles, and chronic inflammation. The inflammatory infiltrate in erosive pustulosis of the scalp may consist of lymphocytes, plasma cells, foreign-body giant cells, and neutrophils. Note the images below. When neutrophils are present in erosive pustulosis of the scalp lesions, subcorneal and spongiform pustules may be noted. [5, 6]
A dense perifollicular infiltrate is composed of lymphocytes, neutrophils, histiocytes, and multinucleated giant cells (hematoxylin and eosin, 200x).
Closer examination shows a predominantly neutrophilic infiltrate with a background of admixed lymphocytes and histiocytes (hematoxylin and eosin, 400x).
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Yellow-brown crusts with atrophy on the vertex scalp.
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Yellow-brown crusts on the vertex scalp.
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A dense perifollicular infiltrate is composed of lymphocytes, neutrophils, histiocytes, and multinucleated giant cells (hematoxylin and eosin, 200x).
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Closer examination shows a predominantly neutrophilic infiltrate with a background of admixed lymphocytes and histiocytes (hematoxylin and eosin, 400x).
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Erosive pustular dermatosis on the bilateral lower extremities in a woman with history of extensive UV exposure.
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Crusts with underlying purulence on the lower extremity.
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Erosive pustulosis of the scalp prior to curettage.
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Erosive pustulosis of the scalp 4 weeks following two treatments of curettage debridement with electrodesiccation performed at 3-week intervals.
