PDT for erosive pustular dermatitis of the scalp: Seeing the light (but reaching a different conclusion)
By Warren R. Heymann, MD
June 9, 2016
Erosive Pustular Dermatitis of the Scalp (EPDS) is a relative common condition, typically seen on the actinically damaged scalps of the elderly men. Lesions characteristically present as hyperkeratotic, crusted erosions with varying degrees of pustulation. Lesions may become secondarily infected. The etiology is unknown, although a neutrophilic reaction to trauma has been suggested. The clinical differential diagnosis may include pemphigus, cicatrical pemphigoid, pustular psoriasis, tinea and non-melanoma skin cancer. EPDS is a diagnosis of exclusion after ruling out neoplastic, infectious, and autoimmune disorders by appropriate biopsies and cultures. Various therapies have been utilized, including potent topical steroids, tacrolimus, topical retinoids, calcipotriol, or systemic therapy with retinoids and zinc sulphate (1). Topical dapsone may be effective. (2)
Photodynamic therapy (PDT) has been described as a causative factor and as treatment of EPDS (1). Lesions have been reported following PDT for the treatment of actinic keratosis (3). Myer reported a successful outcome of PDT in a 75-year-old woman with EPDS that was recalcitrant to other modalities.
Yang et al reported 8 patients with EPDS who underwent gentle curettage of the hyperkeratotic lesions followed by aminolevulinic acid PDT 1 to 2 weeks later. Lesions resolved in 6 patients; 2 patients had residual lesions at 6 weeks follow-up and underwent a second round of treatment. The authors concluded that this protocol “represents and efficacious modality for EPDS.” (5)
There is no argument that their patients improved, but was it because of the PDT? My hunch is that the PDT may or may not be relevant. I would surmise that it’s the gentle curettage that is the key to success. Regarding other therapies, the authors state there has been “limited success partly because of difficulty penetrating the hyperkeratotic crust, especially in lesions exhibiting massive hyperkeratosis.”
There is a Goldilocks phenomenon at play in curetting EPDS — curette too vigorously and the trauma might exacerbate the lesions; curette too lightly and you will not allow whatever therapy you use to foster healing of the lesions.
When treating patients with EPDS, I have found that topical steroids, tacrolimus, and dapsone all have worked well, after the crust has been removed. Perhaps PDT is a useful modality following curettage in patients with EPDS. Of course the best way to analyze this would be with a “split scalp,” curetting both sides, utilizing PDT on one side versus either petrolatum (or one of the many reported treatments). Until such studies are performed, use whatever you’d like — just gently debride first.
1. Aigner B, et al. Sun-induced pustular dermatosis of the scalp – a new variant of erosive pustular dermatosis of the scalp?
2. Broussard KC, et al. Erosive pustular dermatosis of the scalp: A review with a focus on dapsone therapy. J Am Acad Dermatol 2012; 66: 680-6.
3. López V, et al. Erosive pustular dermatosis of the scalp after photodynamic therapy. Dermatol Online J 2012; 15: 18: 13.
4. Meyer T, et al. Erosive pustular dermatosis of the scalp: A successful treatment with photodynamic therapy. Photodermatol Photoimmunol Photomed 2010; 26: 44-5.
5. Yang CS, et al. Aminolevulinic acid photodynamic therapy in the treatment of erosive pustular dermatosis of the scalp. JAMA Dermatol 2016; 152: 694-7.
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