Seborrheic Dermatitis Workup

Updated: Nov 13, 2020
  • Author: Marc Zachary Handler, MD; Chief Editor: William D James, MD  more...
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Laboratory Studies

A clinical diagnosis of seborrheic dermatitis is usually made based on a history of waxing and waning severity and by the distribution of involvement upon examination.



A skin biopsy may be needed in persons with exfoliative erythroderma, and a fungal culture can be used to rule out tinea capitis, although tinea capitis in the adult is rare.


Histologic Findings

Dermatopathologic findings of seborrheic dermatitis are nonspecific, but they may present in an acute or chronic stage. [27] In the acute stage, inflammation is noted perifollicularly and perivascularly. Spongiosis and psoriasiform hyperplasia is often seen, as well as the classic finding, "shoulder” parakeratosis, with parakeratosis around the follicular opening. Neutrophils are often seen in the crust at the margins. Chronic seborrheic dermatitis may appear similar to psoriasis, but psoriasis is distinguished by regular acanthosis, thinned rete ridges, exocytosis, parakeratosis, and an absence of spongiosis. Neutrophils may be seen in both diseases. [27]