Keratosis Pilaris Workup

Updated: May 12, 2022
  • Author: Ally N Alai, MD, FAAD; Chief Editor: Dirk M Elston, MD  more...
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Laboratory Studies

No specific laboratory tests aid in the diagnosis of keratosis pilaris (KP). The diagnosis of keratosis pilaris is very straightforward and is based on a typical skin appearance in areas such as the upper arms. A family history of keratosis pilaris is also very helpful because keratosis pilaris has a strong genetic component. The diagnosis is confirmed on the basis of the physician’s clinical examination findings. A few other medical conditions look similar to keratosis pilaris, and these must be excluded.


Imaging Studies

Imaging studies are not indicated.



Skin biopsy with histopathological examination may be useful in atypical cases.


Histologic Findings

Microscopic examination (histopathology) of keratosis pilaris (KP) lesions shows the triad of epidermal hyperkeratosis, hypergranulosis, and plugging of individual hair follicles. The upper dermis may have mild superficial perivascular lymphocytic inflammatory changes.

The individual papules in keratosis pilaris are thought to arise from excessive accumulation of keratin at the follicular orifice. The overlying epidermis shows mild thickening and plugging of the small follicular orifice.