Actinic Keratosis Workup

Updated: Jun 03, 2021
  • Author: James M Spencer, MD; Chief Editor: William D James, MD  more...
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Laboratory Studies

Blood work is not indicated.



A skin biopsy is indicated to confirm the diagnosis and to rule out invasive squamous cell carcinoma for suspicious or more advanced lesions (ie, those with more pronounced hyperkeratosis, increased erythema, induration or nodularity). [8, 9] A biopsy is also indicated for recurrent lesions or those that are unresponsive to therapy.

Fluorescence with the use of a photosensitizing drug (methyl ester of 5-aminolevulinic acid [ALA], a precursor of protoporphyrin) commonly used during photodynamic therapy (PDT) has been described as a diagnostic tool for actinic keratosis. [10] Areas of involvement, including occult areas of abnormal skin, emit a pink fluorescence with a Wood lamp or photodynamic therapy lamp. [10]


Histologic Findings

Actinic keratosis is characterized by dysplasia and architectural disorder of the epidermis. [1] Keratinocytes of the basal layer are abnormal and are variable in size and shape; cellular polarity is altered, and nuclear atypia is seen. [1] These alterations may extend upward to the granular layer, which may be thinned. Overall, the epidermis exhibits hyperkeratosis and parakeratosis, and irregular acanthosis may be present. [1] In general, hair follicles, sebaceous glands, and apocrine and eccrine ducts are not involved. [1]