Incidence and Time to Development of Malignancies Arising on the Scalp of Patients with Erosive Pustular Dermatosis Based on Sex: A Retrospective Analysis.

To the Editor: Erosive pustular dermatosis (EPD) is an inflammatory condition that typically affects the scalp of older males.1Starace M. Iorizzo M. Trueb R.M. et al.Erosive pustular dermatosis of the scalp: a multicentre study.J Eur Acad Dermatol Venereol. 2020; 34: 1348-1354Crossref PubMed Scopus (16) Google Scholar Its features are nonspecific and diagnosis is often delayed given its clinical resemblance to conditions including folliculitis, dissecting cellulitis, and pemphigus.1Starace M. Iorizzo M. Trueb R.M. et al.Erosive pustular dermatosis of the scalp: a multicentre study.J Eur Acad Dermatol Venereol. 2020; 34: 1348-1354Crossref PubMed Scopus (16) Google Scholar,2Negbenebor N.A. Shayegan L.H. Cohen L.M. Kroumpouzos G. Nonmelanoma skin cancer in the setting of erosive pustular dermatosis of the scalp: a case series and comment on management implications.Dermatol Ther. 2022; 35e15584Crossref PubMed Scopus (4) Google Scholar While the association between EPD and sun damage has been well-established,3Starace M. Alessandrini A. Baraldi C. Piraccini B.M. Erosive pustular dermatosis of the scalp: challenges and solutions.Clin Cosmet Investig Dermatol. 2019; 12: 691-698Crossref PubMed Scopus (10) Google Scholar the incidence and time to development of malignancies has not been studied. Notably, cutaneous malignancies in the setting of EPD have been observed to be aggressive and difficult to treat.4Barilla S. Malviya N. Wang H. Sharon V.R. Squamous cell carcinoma arising in chronic erosive pustular dermatosis.Dermatol Surg. 2022; 48: 250-251Crossref PubMed Scopus (4) Google Scholar We aim to evaluate the incidence and time to development of malignancies arising on the scalp of patients with EPD in clinics associated with a suburban, tertiary care academic center. This is a retrospective analysis of patients with a histological or clinical diagnosis of EPD of the scalp between 2000 and 2021 [Supplementary Fig 1, available via Mendeley at https://doi.org/10.17632/6z45pr5jwr.1]. A total of 80 patients were evaluated for prior and subsequent development of biopsy-proven malignancy on the scalp. Time to event (malignancy free time) was determined using Kaplan-Meier estimation with comparisons between curves assessed via the log-rank test. Proportional hazards model was used to estimate malignancy free time while adjusting for covariates (gender and age at diagnosis of EPD). Overall, 55% (n = 44) of patients developed a cutaneous scalp malignancy after EPD diagnosis, with the majority being males (72.7%, n = 32). Forty-six percent of the patients (n = 37) had a scalp malignancy prior to EPD diagnosis and 51% (n = 19) of this subgroup developed a subsequent malignancy. Squamous cell carcinoma was the most common malignancy (73.5%, n = 34). [Table I]. There was no statistical difference between the malignancy free time for patients who had malignancy on their scalp prior to EPD and those who did not (log-rank test P = .69) or between immunocompromised and nonimmunocompromised patients (P = .27) [Supplementary Table I, available via Mendeley at https://doi.org/10.17632/6z45pr5jwr.1]. Additionally, no significant differences were identified between treatment modalities or treatments by gender [Supplementary Tables II and III, available via Mendeley at https://doi.org/10.17632/6z45pr5jwr.1]. The median time from EPD diagnosis to malignancy diagnosis was 2.44 years (95% CI: 0.63, years—4.62 years) and 3.17 years (95% CI: 2.12, years—not estimable) for males and females, respectively [Fig 1]. Adjusting for age at diagnosis of EPD, the hazard of developing a malignancy was 80% higher for males than females (hazard ratio = 1.80; 95% CI: 0.93, 3.52; P value = .08). Though not statistically significant, after adjusting for gender, for every 1-year increase in age from the diagnosis of EPD the hazard of developing a malignancy increased by 3%.Table IBaseline patient characteristics and diagnosesCharacteristicNumberFrequency (%)Gender Male5366.3 Female2733.7Ethnicity White7796.2 Hispanic11.3 Other22.5Scalp malignancy before EPD diagnosis Yes3746.2 No4353.8EPD diagnosis modality Clinical4961.2 Histological3138.8Scalp malignancy development Yes4455 No3645Type of malignancy Squamous cell carcinoma3477.2 Basal cell carcinoma715.9 Atypical fibroxanthoma24.6 Pleomorphic dermal sarcoma12.3Development of additional scalp malignancy Yes2328.8 No5771.2Number of additional scalp malignancies 1730.4 2730.4 328.7 428.7 500 6313 714.4 800 900 1000 1114.4EPD, Erosive pustular dermatosis. Open table in a new tab EPD, Erosive pustular dermatosis. This study suggests that males may be more likely to develop a scalp malignancy after being diagnosed with EPD, with squamous cell carcinoma being the most common. EPD may serve as a marker of sun damage since the rate of scalp malignancy is relatively high in this population. Therefore, patients with EPD should be monitored closely for the development of malignancy especially if they have become recalcitrant to previously successful therapies. The retrospective and nonrandomized designs are limitations. Additionally, patient characteristics such as hair density, use of sun protection, and Fitzpatrick skin type were not recorded. None disclosed. Letter from the Editor: Aggressive malignancy in the setting of erosive pustular dermatosis of the scalpJournal of the American Academy of DermatologyVol. 89Issue 5PreviewIn this issue of the Journal of the American Academy of Dermatology, Shamloul et al (page 1038) draw attention to the risk of aggressive squamous cell carcinoma arising in the setting of erosive pustular dermatosis (EPD), adding evidence about timing and incidence to prior reports of this serious complication.1,2 EPD is an inflammatory condition that typically affects the scalp of older patients, many of whom have a history of skin cancer of the scalp. As such, it is not surprising that many will have subsequent skin cancers. Full-Text PDF