INTRODUCTION
Hidradenitis suppurativa (HS) is a chronic, often recalcitrant
condition that primarily affects apocrine glandbearing
skin in the axillae, groin and buttocks. Histopathologic
studies show that follicular occlusion rather than inflamed
apocrine glands is the primary diagnostic feature1 in the development
of abscesses and sinus tracts in HS.2 Found most often
in women,3 HS is characterized by swollen, painful, inflamed and
usually suppurative lesions, and the condition can be frustrating,
embarrassing and potentially life-altering to patients. Healing is
often associated with severe scarring.4 Although the exact cause
of HS is not known,5 smoking, obesity, hormonal and genetic factors
are believed to contribute to its development.6
Medical treatment options for HS include antibiotics, glucocorticoids,
isotretinoin, acetretin, cyproterone acetate, oral
contraceptions and cyclosporin, all of which have limited efficacy.
Radical surgery, though locally effective, may produce cosmetically
unacceptable results.7,8 The use of infliximab,9,10,7 etanercept,11
adalimumab12 and efalizumab13 is currently under investigation.
Photodynamic therapy (PDT) is a therapeutic harnessing of photochemical
reactions induced by a variety of light sources including
blue, red, or broadband intense pulsed light (IPL). The most frequently used photosensitizing agent is 20% 5-aminolevulinic acid (ALA as
Levulan, Dusa Pharmaceuticals). PDT with ALA is FDA approved for
the treatment of actinic keratoses of the scalp and has been used off
label to treat a variety of skin conditions, including acne vulgaris.
A literature search conducted in November 2008 revealed three
articles14,2,5 exploring the use of PDT to treat HS. In the first report,
14 Gold and colleagues obtained 75 percent to 100 percent
clinical improvement in four patients after three to four treatments
with short-contact ALA and blue light activation. Strauss
and colleagues,2 using four-hour contact ALA (20% in Unguentum,
Merck, Darmstadt, Germany) and activation with a 633-nm
diode laser or broadband red light source (570-640 nm), reported
no significant improvement in all of four patients after one to
three treatments. Two years later, Gold5 reviewed current therapies
for HS and focused on the use of ALA PDT. The findings
of Gold and colleagues (2004) with short-contact ALA encour-
