Diaper Rash Workup

Updated: Aug 25, 2021
  • Author: Rania Dib, MD; Chief Editor: Kirsten A Bechtel, MD  more...
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Laboratory Studies

The primary forms of diaper rash generally can be diagnosed clinically. Laboratory studies have few indications and limited utility. A complete blood cell count may be helpful, especially if a fever is present and a secondary bacterial infection is suspected.

The finding of anemia in association with hepatosplenomegaly and the appropriate rash may suggest a diagnosis of Langerhans cell histiocytosis or congenital syphilis.

When suspecting congenital syphilis, relevant serology should be sent. Dark field microscopic examination for spirochetes from any bullous lesion scrapings can be performed.

Serum zinc level of less than 50 mcg/dL can confirm acrodermatitis enteropathica.

Gram stain or culture of the characteristic bullae of impetigo for S aureus can confirm this diagnosis.

Routine cultures demonstrate polymicrobial infections (eg, streptococci, Enterobacteriaceae, and anaerobes) in nearly one half of cases.


Other Tests

Potassium hydroxide (KOH) scrapings from a fresh papular or pustular lesion may demonstrate pseudohyphae in suspected cases of candidiasis. However, these may be absent in long-standing cases.

Finding mites, ova, or feces on a mineral oil preparation of a burrow scraping can confirm the diagnosis of scabies.



Skin biopsy can be performed to help differentiate granuloma gluteale infantum from granulomatous and neoplastic processes.

Histopathology, granuloma gluteale presents as nonspecific dermal inflammatory infiltrate composed of neutrophils, lymphocytes, histiocytes, plasma cells, occasional giant cells, and eosinophils, sometimes with an increase in the number of capillaries.

Examination of granuloma gluteale using an electron microscope reveals 3 types of giant cells: in the first type, the cells have widely enlarged endoplasmic reticulum; in the second type, they phagocytize erythrocytes; and in the third type, they have vesicles and granules and are similar to histiocytes. The name granuloma gluteale infantum is a misnomer since no granulomas are found in these lesions.

Skin biopsy also is used to confirm the diagnosis of Langerhans cell histiocytosis.