Forum for Nordic Dermato-Venereology Nr2,2017 | Page 8

Educational Review Erosive Pustular Dermatosis of the Scalp N icolas K luger , R egional E ditor , F inland Helsinki University Central Hospital and University of Helsinki, Dermatology, Allergology and Ve- nereology, FI-00029 Helsinki, Finland. E-mail: [email protected] Introduction Erosive pustular dermatosis of the scalp (EPDS) is a rare chronic disease characterized by sterile painful pustules, erosions and crusts on the scalp. It was first described in the late 1970s by Burton (1) and Pye (2). EPDS affects mainly, but not exclu- sively, elderly women (mean age 70 years). Young adults can also be affected (3, 4). Lesions extend slowly over months or years, leading to marked cicatricial alopecia (3, 5). EPDS has a protracted evolution, responds poorly to treatment, and has a negative aesthetic impact. Evolution to local squamous cell carcinoma occurs exceptionally (6), probably related to pre-ex- isting lesions, such as actinic keratoses. Regular follow-up is therefore advised. The condition is not well-known, and is therefore often overlooked or misdiagnosed; it may be years before patients are offered adequate treatment (5). Triggering factors Underlying androgenetic alopecia and actinic damage are not rare (3). Injury to the scalp (5) is often reported to have occurred months before onset of symptoms. Causes of in- jury include trauma, wounds (e.g. due to herpes infection), contusions, local burns (e.g. due to irritative local/chemical treatment, such as 5-fluorouracil cream, or topical tretinoin, liquid nitrogen/cryosurgery, photodynamic therapy, CO 2 laser, Fig. 1. Cicatricial alopecia of the vertex with erosions, crusts, and yellow pustules in an elderly patient. 38 or radiotherapy), surgery, skin grafts, prolonged exposure of a bald scalp to ultraviolet (UV) light, and zinc deficiency (5). In addition, various autoimmune conditions have been reported to be associated with EPDS (e.g. rheumatoid arthritis, Hashi- moto thyroiditis, and autoimmune hepatitis). Clinical signs Clinically EPDS affects mainly the vertex. The scalp becomes inflamed, with yellow pustules, yellow or haemorrhagic crusts, atrophy of the scalp skin, hair thinning, which slowly evolves into progressive cicatricial alopecia (3) (Figs 1–2). Association with erosive pustular dermatosis (EPD) of the legs has been reported (3). Some authors consider EPDS and EPD of the legs to represent a single disease (7). Laboratory and microscopic findings Laboratory findings in EPDS are usually unremarkable, apart from increased acute-phase reactant level (CRP). Zinc deficien- cy has sometimes been reported and should be investigated at time of diagnosis, at least. Local bacterial and mycological swabs are usually negative, except in the case of secondary colonization with Staphylococcus aureus or Candida albicans. Pustule swabs should therefore be repeated if necessary (e.g. in the case of large pustules, recurrence, or treatment resistance). Fig. 2. Localized form of erosive pustular dermatosis of the scalp. Forum for Nord Derm Ven 2017, Vol. 22, No. 2