Are You Confident of the Diagnosis?
What you should be alert for in the history
Erosive pustular dermatitis (or dermatosis) of the scalp [EPDS] is diagnosed clinically in suspected individuals with certain risk factors. Patients tend to be elderly (older than 65 years) and predominantly Caucasian, with a preceding history of trauma or injury to the scalp. Other preceding causes include skin grafting (Figure 1), radiation therapy, cryotherapy, topical chemotherapy creams (5-fluorouracil), and surgery. Occasionally EPDS may occur de novo in patients with significant actinic damage to the scalp.
An alternative term for EPDS that highlights chronic actinic damage as a potential etiology, is known as “chronic actinic erosive dermatitis of the scalp and extremities.”
Characteristic findings on physical examination
Erosive pustulosis of the scalp is characterized by crusted plaques, sterile pustules, or frank erosions that often exude purulent material when manipulated (Figure 2, Figure 3). Frequently, EPDS will occur on areas of thinned or absent scalp hair. The sequelae of erosive pustulosis are often a scarring alopecia which can predispose patients to recurrent bouts of EPDS. Elderly Caucasian patients are almost exclusively affected by EPDS, although other individuals from other races (eg, Hispanic) have been identified.
Expected results of diagnostic studies
No specific testing is required to establish the diagnosis of erosive pustulosis. Cultures of purulent material are frequently negative, but can be taken to identify a dominant organism if infection is suspected. Routine histopathology is also unnecessary, but demonstrates loss of hair follicles, orthokeratotic and parakeratotic scale, dermal atrophy, erosions, and chronic inflammation (lymphocytes, plasma cells, giant cells, and neutrophils).
The clinical presence of pus correlates with subcorneal and spongiotic neutrophils histologically. Finally, while immunofluorescence studies are unremarkable in EPDS, a case study in 2009 demonstrated discontiguous IgM and C3 deposition along the basement membrane and dermal vessels in erosive pustulosis of the leg in a patient with ankylosing spondylitis.
The differential diagnosis of EPDS is extensive, but can be divided into infectious, inflammatory, neoplastic, and autoimmune causes.
Infectious differential diagnoses include chronic bacterial folliculitis, gram negative folliculitis, chronic mucocutaneous candidiasis, tinea capitis (including kerion) and impetiginized chronic actinic damage of the scalp. Bacterial, fungal, and acid-fast bacilli cultures should be taken in suspected cases to rule out these etiologies. Furthermore, impetiginized crust overlying the sterile pustules of EPDS could lead to false-positive cultures and derail definitive treatment.
Kerion formation with boggy induration is uniquely distinct in that a large subcutaneous nodule without frank ulceration is the norm, differentiating it from EPDS. Pyoderma vegetans has also been described as an infectious variant of EPDS associated with Staphylococcus aureus overgrowth.
Inflammatory conditions such as dissecting cellulitis of the scalp, folliculitis decalvans, scarring (cicatricial) alopecias, subcorneal pustular dermatosis, and pyoderma gangrenosum can mimic erosive pustulosis of the scalp. Diagnostic biopsies will aid in ruling out these seemingly clinically similar entities. Folliculitis decalvans routinely presents with tufted folliculitis and frank perfollicular pustules on hair bearing scalp. Subcorneal putular dermatosis (Sneddon-Wilkinson disease) usually involves flaccid pustules in intertriginous regions of the trunk and extremities. Pyoderma gangrenosum presents most commonly on lower extremities with undermined ulcerations and erosions and very little scale.
Neoplastic entities such as squamous cell carcioma (SCC) and angiosarcoma (AS) frequently display some physical features shared with erosive pustular dermatosis. Both tumors routinely arise on the scalp, with SCC similarly containing profound crust and scale, while angiosarcoma frequently ulcerates in advanced disease. Histology is paramount in establishing a firm diagnosis if these tumors are suspected.
The most challenging differential diagnoses to exclude are autoimmune disorders; namely, pemphigus foliaceous and vulgaris, cicatricial pemphigoid, and temporal (giant cell) arteritis. Direct immunofluorescence (DIF, via skin biopsy in buffered media, Quest Diagnostics test 18899X) and indirect immunofluorescence (IIF, commercially available serum antibodies, Quest Diagnostics test 16690X) studies will assist in ruling out pemphigus and pemphigoid.
The cicatricial pemphigoid variant known as Brunsting-Perry can closely mimic the clinical features of EPDS, and frequently has negative IIF circulating autoantibodies, and variable DIF results. Brunsting-Perry pemphigoid often involves the scalp and results in scarring alopecia which may confound the definitive differentiation from EPDS.
Who is at Risk for Developing this Disease?
As stated above, EPDS afflicts the elderly (older than 65 years) and predominantly Caucasian patients, with a preceding history of trauma or injury to the scalp. Other preceding causes include skin grafting, radiation therapy, cryotherapy, topical chemotherapy creams (5-fluorouracil), ablative laser treatments, and surgery. Occasionally EPDS may occur de novo in patients with significant actinic damage to the scalp, or after seemingly insignificant injuries (ie. abrasions). A 2007 review revealed a predilection for women with a 2-3:1 female to male incidence ratio.
More recently, reports of erosive pustulosis have been associated with myasthenia gravis (scalp and leg involvement), ankylosing spondylitis (leg involvement only), rheumatoid arthritis, following herpes zoster, and photodynamic therapy (PDT) have been described. Interestingly, PDT has also been reported as a potential treatment of EPDS in refractory cases.
An infant with Klippel-Feil syndrome (webbed neck, cervical spine fusion, and a low hairline) has been reported to have EPDS. Infants with other perinatal scalp traumas (caput succedaneum) have also been described with features consistent with EPDS.
What is the Cause of the Disease?
The etiology of erosive pustular dermatosis of the scalp or extremities remains elusive and unknown since its initial description in 1979 by Pye, Peachey, and Burton. Several investigators have suggested that the presence of chronic actinic damage, combined with an inciting injury, promotes a neutrophil-rich environment through an imbalance of stimulating cytokines and chemokines.
As stated above, EPDS and erosive pustulosis of the leg are well documented to occur after a variety of insults in at-risk individuals, particularly those with a background of chronic actinic damage. Proposed causes include skin grafting, radiation therapy,cryotherapy, cutaneous surgery, perinatal birth trauma to the scalp, topical chemotherapy creams (5-fluorouracil and imiquimod), topical tretinoin, herpes zoster, laser resurfacing, ALA- and MAL-photodynamic therapy. and rarely, baseline systemic autoimmune diseases.
Interestingly, a single case of EPDS has been shown to develop in a patient receiving gefitinib, and epidermal growth factor receptor inhibitor (EGFR), and radiotherapy for brain metastases of primary lung cancer. The role to which gefitinib initiated the EPDS remains unclear, but its mechanism of action belies one aspect of the cellular events proposed by some authors by preventing epidermal maturation and migration following radiation therapy.
In 1999 Jaffe, Heymann, and Lawrence described a series of surgical patients with failure of their face and scalp wounds to fully re-epithelialize. They proposed that disturbances in the arachadonic acid metabolic pathways retarded epidermal proliferation. This is supported by instances in which NSAIDS (ibuprofen) and ultrapotent topical corticosteroids promote rapid healing in EPDS by inhibiting the phospholipase A2 enzyme, amongst other cellular and molecular targets such as Laminin, interleukin-1, fibronectin, and transforming growth factor-beta (TGF-B). Appropriately, these authors coined the term “epidermal maturation arrest” syndrome as a surgical subset of EPDS.
Systemic Implications and Complications
No systemic complications are routinely described in association with erosive pustulosis of the scalp. As with any patient with a chronic wound, a review of dietary intake for adequate calories and protein through serologic albumin levels, and micronutrients such as vitamin C, iron, folate, B12 is prudent. Additionally, if pyoderma gangrenosum is being strongly considered in the differential diagnosis, a thorough work-up for inflammatory bowel disease should be coordinated with the primary care physician.
In 1980, Lovell and colleagues described cutaneous carcinoma arising within preexisting EPDS. As with any long-standing wound or inflammatory process, degeneration into a Marjolin’s ulcer (squamous cell carcinoma or basal cell carcinoma) should be entertained when traditional therapy fails.
A number of cases in which patients have concurrent autoimmune diseases have been described. These conditions include myasthenia gravis, thyroiditis, Takayasu’s arteritis, autoimmune hepatitis, and rheumatoid arthritis.
High-potency topical steroids
Photodynamic therapy (ALA-PDT)
Optimal Therapeutic Approach for this Disease
High-potency topical steroids remains the mainstay and first-line treatment of EPDS. Once- to twice-daily applications normally result in rapid resolution or control of the condition within weeks to months, with very little complications in the short run. If a case appears refractory, the addition of topical tacrolimus is a reasonable approach that is well described in the literature.
Third-line topical treatment with either calcipotriol or photodynamic therapy can be attempted prior to initiating sytemic oral medications, although worsening of the condition has also been described with photodynamic therapy using methylaminolevulanic acid (MAL-PDT).
Systemic medications should be used after topical treatments have been exhausted and treatment failures well documented. Ibuprofen at levels as low as 200mg twice to three times daily have been shown to aid in clearance, if the patient can tolerate the medication and does not currently struggle with gastritis or gastric ulceration. Oral retinoids have shown promise for refractory cases of erosive pustulosis of the scalp and leg.
Finally, the antineutrophilic properties of prednisone and dapsone may be attempted if all else fails. It is imperative that G6-P-D deficiency be excluded prior to therapy with dapsone, and subsequent dose-related anemia and agranulocytosis, and methemoglobinemia, monitored with weekly and then monthly serology.
Therapy should be monitored by the physician every 2 to 4 weeks with a clinical assessment and digital photographs to accurately document responses or failures to medication regimens. If the patient fails to appreciably respond to treatment at 4-week intervals, then topical or systemic treatment changes should be entertained. Spouse, caretaker, or home-nursing should be educated on how to apply the medications and how to monitor the lesions for improvement or worsening degeneration.
If dapsone, prednisone, acitretin, or isotretinoin are being used, then laboratory monitoring protocols (as mentioned above) should be strictly followed. Although zinc has been anecdotally used, patient expectations should be kept low and its use reserved for adjunctive treatment only.
Unusual Clinical Scenarios to Consider in Patient Management
Failure for EPDS to respond to first-line treatment with high-potency topical steroids should prompt a reevaluation of the diagnosis. Elimination of any persistent triggering factors (eg, infection, debridement or cryotherapy, amongst others) should be completed.
As with any patient struggling with a chronic wound, a review of dietary intake for adequate calories and protein through serologic albumin levels, and micronutrients such as vitamin C, iron, folate, B12 is prudent. Additionally, if pyoderma gangrenosum is being strongly considered in the differential diagnosis, a thorough work-up for inflammatory bowel disease should be coordinated with the primary care physician.
Atypical mycobaterial infections, atypical presentations of routine infections, and autoimmune disorders (eg, pemphigus and pemphigoid) should also be ruled out as an occult cause of the clinical scenario.
What is the Evidence?
Pye, RJ, Peachey, RD, Burton, JL. “Erosive pustular dermatosis of the scalp”. Br J Dermatol. vol. 100. 1979. pp. 559-66. (The seminal article that initially described EPDS. Six elderly women presented with chronic, erosive, pustular lesions of the scalp with scarring alopecia. Investigations were negative except for biopsies, which revealed chronic inflammation with an increased plasma cell infiltrate. The patients did not respond to antibiotics but did improve with potent topical steroids.)
Lovell, CR, Harman, RR, Bradfield, JW. “Cutaneous carcinoma arising in erosive pustular dermatosis of the scalp”. Br J Dermatol. vol. 103. 1980. pp. 325-8. (Highlights the challenge in managing chronic wounds and the need for vigilance when treating EPDS. Cutaneous malignancies are in the differential for erosive pustulosis, and any chronic wound is theoretically at risk for malignant degeneration.)
McDonaagh, AJ, Bleehen, SS. “Kerion mascquerading as erosive pustular dermatosis of the scalp”. Br J Dermatol. vol. 124. 1991. pp. 507-8. (Another article emphasizing the need for exhaustive efforts to rule out correctable causes of scalp inflammation, when making the diagnosis of EPDS – which is essentially a diagnosis of exclusion.)
Wantanabe, S, Takizawa, K, Hashimoto, N. “Pustular dermatosis of the scalp associated wtih autoimmune diseases”. J Dermatol. vol. 16. 1989. pp. 383-7. (A case of culture-negative EPDS responding to steroids in a 36-year old with Hashimoto’s thyroiditis, autoimmune hepatitis, and Takayasu’s aortitis. Similar articles are available in the setting of rheumatoid arthritis and myasthenia gravis.)
Patton, D, Lynch, PJ, Fung, MA. “Chronic atrophic erosive dermatosis of the scalp and extremities: a recharacterization of eruptive pustular dermatosis”. J Am Acad Dermatol. vol. 57. 2007. pp. 421-7. (The first collection of United States cases of erosive pustulosis. Eleven patients were identified (9 scalp, 2 extremities). The skin was chronically actinically damaged or atrophic in 9 of the 11 patients. All lesions resolved or improved with high-potency steroids or tacrolimus. Intact pustules were rarely clinically present, despite the title of the condition.)
Kim, KR, Lee, JY, Kim, MK. “Erosive pustular dermatosis of the scalp following herpes zoster: successful treatment with topical tacrolimus”. Ann Dermatol. vol. 22. 2010. pp. 232-4. (This case report and review identifies herpes zoster as a nidus for EPDS formation. Additionally, topical tacrolimus was successfully used to treat the condition.)
Meyer, T, Lopez-Novarro, N, Herrera-Acosta, E. “Erosive pustular dermatosis of the scalp: a successful treatment with photodynamic therapy”. Photodermatol Photoimmunol Potomed. vol. 26. 2010. pp. 44-5. (Methyl 5-aminolaevulinic acid was successfullly used to treat a 75-year-old female with EPDS.)
Jaffe, AT, Heymann, WR, Lawrence, N. “Epidermal maturation arrest”. Dermatol Surg. vol. 25. 1999. pp. 900-3. (A series of three cases in which failure to fully epitheliaize scalp and facial surgical wounds resembled EPDS. High-potency topical steroids or ibuprofen were used to promote reepithelialization through a suggested disruption of the arachadonic acid pathway. Similar findings have been decribed by other authors after neurosurgical procedures and related scalp treatments.)
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