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Delayed wound healing on the scalp following treatment of actinic keratoses: Erosive pustular dermatosis of the scalp.

To the Editor: In their article, Quaedvlieg et al. reported three cases of delayed wound healing on the scalp following treatment of actinic keratoses. Those three patients presented chronic erosive and crusty lesions on the scalp with a mixed bacterial flora in the wound cultures. The therapy with antiseptic solutions, local and systemic antibiotics, or topical steroids was partially efficient. This chronic eruption is very suggestive for erosive pustular dermatosis of the scalp. Erosive pustular dermatosis of the scalp is a rare chronic disease with extensive pustular lesions, erosions, and crusting of the scalp, leading ultimately to scarring alopecia. The disease is characterized by the development of sterile pustular lesions with a nonspecific inflammatory reaction of the scalp that typically develops in long-standing atrophic sun-damaged skin changes. Local trauma to this atrophic skin acts as a triggering factor. Erosive pustular dermatosis of the scalp may occur after treatment of actinic keratoses or squamous cell carcinoma by X-ray radiation therapy, skin grafting, fluorouracil cream, or topical tretinoin. We recently reported a case of erosive pustular dermatosis of the scalp after resurfacing carbon dioxide laser therapy for scalp actinic keratoses, which we have treated with topical 0.1% tacrolimus ointment. The pathophysiologic mechanisms of the inflammatory process observed in erosive pustular dermatosis of the scalp remain unclear. Histologic features are not specific, with a spectrum of inflammatory changes involving epidermis and dermis, ulceration, atrophy, or hyperkeratosis and a reduced number or absence of hair follicles. Microorganisms found in erosive pustular dermatosis of the scalp probably represent a secondary colonization rather than a primary infection. Potent topical corticosteroids have been widely used in rosive pustular dermatosis of the scalp with a variable and inconsistent response. Nevertheless, the prolonged use of potent topical corticosteroids on atrophic skin may be deleterious. Topical tacrolimus is a potent anti-inflammatory and immunosuppressive molecule that is devoid of many side effects of topical corticosteroids such as epidermal atrophy, striae-distensae, or telangiectasias. In our report topical tacrolimus has been very effective in two erosive pustular dermatosis of the scalp patients, with rapid control of the inflammatory process and an improvement of the atrophic condition. Thus, we want to stress the possibility of erosive pustular dermatosis of the scalp as well as delayed wound healing following treatment of actinic keratoses and propose topical tacrolimus as an interesting therapeutic alternative in steroid resistant cases. There is concern, however, about potential cutaneous carcinogenic effects associated with long-term use of topical tacrolimus on ultraviolet radiation–exposed skin. In the absence of further data about this potential carcinogenic effect after long-term use on photodamaged skin, erosive pustular dermatosis of the scalp patients should be carefully followed-up, especially after tacrolimus treatment.