Topical Sensitizers in Alopecia Areata

Amy J. McMichael; Robert L. Henderson, Jr.


Dermatology Nursing. 2004;16(4) 

In This Article

Abstract and Introduction

Though many therapies exist for alopecia areata, one of the most unique is topical sensitization. By altering the pathogenic inflammatory response with few side effects, sensitizers offer an attractive treatment option for many patients with alopecia areata, including those who have previously failed more traditional treatments and those who have extensive disease.

Alopecia areata (AA) is an autoimmune disease of the hair follicle resulting in patchy or total hair loss from any area on the body. Although many forms of alopecia exist, alopecia areata is distinctive for its circular, nonscarring involvement of the scalp (see Figure 1) (Hordinsky, 2001). While AA is seen throughout all populations with an equal incidence in men and women (Muller & Winkelmann, 1963), it is more common in younger ages. An estimated 60% of those who develop AA do so before the age of 20 years (Price, 1991).

Moderately severe alopecia areata

Histologically, inflammation surrounds the follicular root, thus inducing affected hairs to transition into the falling out phase (telogen phase) (Whiting, 1995). Involved hairs that do not fall out completely have a characteristic exclamation point appearance as they taper towards the base and can frequently be found at the edges of active lesions. The involvement can be so widespread as to involve the entire scalp (alopecia totalis) or entire body (alopecia universalis).

While the hair loss of AA itself is not usually symptomatic, psychosocial effects of the hair loss are often significant. Another important caveat regarding AA is the common association with other autoimmune diseases. Of these, thyroid disease and vitiligo are the most common (Muller & Winkelmann, 1963).

Therapy for AA is primarily directed at halting the underlying inflammation. Traditional therapies for alopecia areata include topical, intralesional, and, rarely, systemic corticosteroids as well as PUVA, minoxidil, and anthralin (Madani & Shapiro, 2000). More recent treatments include imiquimod (Skinner, 2003) and topical sensitizers. Corticosteroids are probably the most effective at decreasing the inflammation but carry significant risks for side effects, particularly if used systemically. Topical and intralesional corticosteroids are usually used as first-line treatments for patchy disease. Treatment of extensive AA is far more challenging. For instance, intralesional corticosteroids are often too painful for treatment of the entire scalp.

Of the other treatments available for AA, topical sensitizers are one of the most unique and include dinitrochlorobenzene (DNCB), squaric acid dibutylester (SADBE), and diphencyprone (DPCP) (Madani & Shapiro, 2000). In this review, the unique immunomodulatory functions of topical sensitizers in the treatment of AA will be discussed, and the mechanisms of the treatment, efficacy, and potential side effects of this treatment reviewed.


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