Pemphigus Foliaceus Workup

Updated: Apr 21, 2019
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Dirk M Elston, MD  more...
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Workup

Laboratory Studies

Immunofluorescence using both direct techniques and indirect techniques is the most reliable method to diagnosis pemphigus. [40] Because of the rare occurrence of pemphiguslike antibodies, pemphigus cannot be diagnosed by indirect immunofluorescence (IIF) alone and must be confirmed by direct immunofluorescence (DIF). With the use of 2 appropriate substrates (ie, monkey esophagus [or human skin] and guinea pig esophagus and standardized conjugates), in IIF, PV and pemphigus foliaceus patterns are different; PV stains throughout the epidermis, and pemphigus foliaceus stains only in the upper epidermis, whereas, with DIF, the patterns are similar. With a DIF study, cell surface immune deposits are often present throughout the entire epidermis in both pemphigus foliaceus and PV. Using DIF on telogen hair outer root sheath may be beneficial for diagnosis and follow-up, irrespective of the presence of scalp lesions. [41]

Immunologic examination with DIF testing shows IgG in the intercellular space, mainly in the upper parts of the epidermis; an IIF study documents the presence of circulating pemphigus antibodies, especially with a guinea pig esophagus used as a substrate. One IIF study suggested that using both a monkey esophagus and the human skin increases the sensitivity and aids in distinguishing pemphigus foliaceus from PV. In PH, IgG deposits are evident in the upper epidermis, with circulating IgG to the epidermal cell surface. The subcorneal pustular dermatosis type of IgA pemphigus foliaceus has IgA deposition on the upper epidermal cell surfaces and circulating IgA antibodies to the epidermal cell surfaces. Desmogleins 1 and 3 are the major cell surface target molecules in patients with PH. In the unusual instance when PV becomes pemphigus foliaceus, or vice versa, the clinical alteration is associated with a shift in the antidesmoglein autoantibody profile.

Other methods, such as ELISA [42] and immunoblot assays, [43] can be used, but they require highly purified antigens to give similar results. The sensitivity for PV and pemphigus foliaceus antibodies is more than 98% in at least the renowned laboratory of Jarzabek-Chorzelska and associates, [40] with their many decades of experience. Histologic examination is useful, but it is not the preferred method for diagnosing pemphigus foliaceus because it cannot replace a highly reliable DIF method.

Another less experienced laboratory found ELISA to be superior to an IIF study for serodiagnosis of pemphigus foliaceus at various stages of disease activity. [44]

Pemphigus foliaceus arising during the administration of D-penicillamine was described in an elderly patient in whom withdrawal of D-penicillamine resulted in improvement of the skin lesions and ELISA scores for anti–desmoglein 1 antibodies revealed a rapid decline. [45]

The sensitivity and specificity of a novel multisubstrate immunofluorescence technique called BIOCHIP was evaluated in 35 patients, 21 with pemphigus vulgaris and 14 with pemphigus foliaceus, and the technique was found to be beneficial in differentiating these two types of pemphigus. [46]

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Histologic Findings

Pemphigus foliaceus begins as acantholysis of the upper epidermis, often resulting in a subcorneal cleft. It usually enlarges and detaches without bullae formation, though a bulla may form showing acantholysis at both the roof and the floor. More established lesions may have acanthosis and mild-to-moderate papillomatosis. Hyperkeratosis and parakeratosis may also be evident, with dyskeratotic cells within the granular layer. These features may be particularly pronounced in long-standing PE. A mild dermal lymphocytic infiltrate occurs, often with the presence of eosinophils. Eosinophilic spongiosis may also be noted, especially in PH.

Histologic view shows the typical pattern of a det Histologic view shows the typical pattern of a detached stratum corneum without bullae formation. Pigmentary incontinence is prominent in the dermis, reflecting the patient's 9-year history of recurrent superficial bullae.
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