Erosive Pustulosis of the Scalp

Erosive pustulosis of the scalp was first described by Pye, Peachey, and Burton in 1979 as a rare disorder of uncertain etiology seen in elderly individuals.[3] Erosive pustulosis of the scalp is characterized by sterile pustules, erosions, and crusted lesions, as shown in the images below.[4] These lesions result in scarring alopecia of the involved areas.[5] Although its etiology remains unknown, erosive pustulosis of the scalp is seen in atrophied skin secondary to actinic damage or exposure to local trauma. Cases of erosive pustulosis of the scalp have been reported following trauma, surgery, skin grafting, thermal burn, laser, cryotherapy, sunburn, and topical chemotherapy, among others.[1, 5, 6, 7]

Yellow-brown crusts with atrophy on the vertex scalp.

Yellow-brown crusts on the vertex scalp.

Cases of erosive pustulosis affecting the extremities have also been reported,[6, 8] as shown in the images below.

Erosive pustular dermatosis on the bilateral lower extremities in a woman with history of extensive UV exposure.

Crusts with underlying purulence on the lower extremity.

The etiology of erosive pustulosis of the scalp is poorly understood; however, several factors that may be related to the pathogenesis of the disease.

Cutaneous atrophy from any cause, but most commonly actinic damage, is a predisposing condition to erosive pustulosis of the scalp and seems to be present in almost all reported cases.[6]

Trauma and tissue damage may play a role in the development of erosive pustulosis of the scalp. Inflammatory triggers associated with erosive pustulosis include herpes zoster, iatrogenic insults of cryotherapy, topical chemotherapy (including topical ingenol mebutate 0.015% gel),[9] excisional surgery, skin grafting,[5, 6] hair transplantation,[10] thermal burn,[7] sunburn,[1] topical methyl aminolevulinate photodynamic therapy,[11] immunosenescence,[12] and carbon dioxide laser therapy.[13] A localized form of erosive pustulosis of the scalp has been reported after implantation of a cochlear implant.[14] A single case study reported the development of erosive pustular dermatosis of the scalp after contact dermatitis from a prosthetic hair piece.[15] There have also been two cases of erosive pustular dermatosis of the scalp occurring after treatment with topical 3.75% imiquimod for actinic keratoses of the scalp.[16] It is important to keep in mind that association should not be confused with causality. Although the above cited reports have described various medications, infections, surgical procedures, or topical agents occurring together with erosive pustulosis, it is unknown if they play a direct role in the pathogenesis of this condition.

Chronic inflammation is noted in histology studies, and it clearly plays a role in the persistence of erosive pustulosis of the scalp.[6]

Frequency

Previously described as a rare condition, increases in reporting have raised the likelihood that erosive pustulosis of the scalp is more common than previously thought.

Race

Erosive pustulosis of the scalp is found more commonly in white persons.[17]

Sex

Erosive pustulosis of the scalp has a female predominance, with a female-to-male ratio of approximately 2:1.[6]

Age

Erosive pustulosis of the scalp primarily affects elderly persons, although cases have been reported in young patients following surgical excisions and burns.[6, 7, 18]

Erosive pustulosis of the scalp is a chronic condition. Erosive pustulosis of the scalp causes mild-to-moderate pruritus and pain. The appearance of the erosions and crusts are embarrassing to the patient, and the end result is scarring alopecia. Erosive pustulosis of the scalp is not a fatal condition.

Sun protection is generally advised to maintain remission.[17]

No specific cause of erosive pustulosis of the scalp has been identified, but actinic damage is a definite predisposing factor. Trauma, infection (herpes zoster), topical agents, surgical treatments, and various other inflammatory factors may trigger the condition.

In erosive pustulosis of the scalp patients, a history of trauma or long-term sun exposure to the affected area can usually be established. Erosive pustulosis of the scalp is generally chronic and may have associated pruritus and/or pain. Patients with extremity involvement may report a history of chronic leg ulcers or chronic venous insufficiency.[19]

Patients present with varying degrees of scarring associated with yellow-brown crusts, erosions, purulent drainage, pustules, and lakes of pus. Pustules may not be visualized, and, when seen, they are usually flattened and contain little or no fluid. Skin surrounding the erosions is almost always atrophic. Purulence may suggest infection, but edema, warmth, and regional lymphadenopathy are typically absent.[6]

Malignancy may develop in areas involved by erosive pustulosis of the scalp. Additionally, recurrence of erosive pustulosis of the scalp has been reported with cessation of treatment, but it tends to respond well to restarting the initial treatment.[5] Secondary infection may also occur.

In erosive pustulosis of the scalp, direct immunofluorescence studies on biopsy tissue may be considered to rule out immunobullous disorders. Results are typically negative in persons with erosive pustulosis of the scalp. A case of erosive pustulosis of the leg has shown discontinuous immunoglobulin M and C3 deposition in the basement membrane and some dermal blood vessels.[19]

Bacterial, acid-fast bacilli, and fungal cultures of purulent material and/or tissue should also be considered. While the pustules of erosive pustulosis of the scalp should be sterile, superinfection of the overlying crust may lead to false-positive culture results.

Erosive pustulosis of the scalp is a clinical diagnosis. No imaging is necessary.

A skin biopsy should be considered to exclude carcinoma, since it may be difficult to distinguish squamous cell carcinoma from erosive pustular dermatosis of the scalp. 

Histopathologic findings in erosive pustulosis of the scalp are nonspecific. Parakeratotic and orthokeratotic scales may be noted in association with atrophy, erosion, loss of hair follicles, and chronic inflammation. The inflammatory infiltrate in erosive pustulosis of the scalp may consist of lymphocytes, plasma cells, foreign-body giant cells, and neutrophils. Note the images below. When neutrophils are present in erosive pustulosis of the scalp lesions, subcorneal and spongiform pustules may be noted.[5, 6]

A dense perifollicular infiltrate is composed of lymphocytes, neutrophils, histiocytes, and multinucleated giant cells (hematoxylin and eosin, 200x).

Closer examination shows a predominantly neutrophilic infiltrate with a background of admixed lymphocytes and histiocytes (hematoxylin and eosin, 400x).

High-potency topical steroids have historically been the mainstay of treatment, and frequently the condition responds rapidly.[1, 7] Topical tacrolimus ointment has also been reported to be helpful, both alone and in addition to oral prednisone.[14, 22, 23, 24] Other treatments reported to be effective include topical and oral retinoids, topical calcipotriol, and oral zinc sulfate, but experience is limited and results appear varied.[5, 6] A single case report described significant improvement following 3 weeks of cyclosporine 3 mg/kg/day in a patient unresponsive to 4 weeks of topical clobetasol, with recurrence following withdrawal of cyclosporine.[25] An additional report described improvement with topical dapsone in four patients, the majority of whom had tried multiple topical and oral therapies with no success.[26] However, once again, evidence regarding these treatments is limited to case reports and case series. Erosive pustulosis of the scalp may recur following treatment.

In the authors’ experience, a highly successful treatment plan includes debridement of the overlying crust with curettage, followed by electrodessication and application of topical mupirocin 2% (applied by the patient once or twice daily). A culture is taken prior to treatment to rule out secondary infection, and biopsy specimens are obtained from any regions suggestive of carcinoma. The patient is seen every 2-3 weeks until lesions have completely resolved, which generally requires no more than three treatments. See the images below.

Erosive pustulosis of the scalp prior to curettage.

Erosive pustulosis of the scalp 4 weeks following two treatments of curettage debridement with electrodesiccation performed at 3-week intervals.

Additional therapeutic modalities used in conjunction with curettage have been reported successful, including application of a novel silicone gel dressing (Stratamed) immediately following curettage and the use if aminolevulinic acid photodynamic therapy 1-2 weeks following curettage.[27, 28, 29] Although erosive pustulosis of the scalp has been reported to be associated with photodynamic therapy, it was also reported to resolve with photodynamic therapy following curettage in another patient.[30] However, the limited data make it unable to be determined if debridement alone would have exhibited similar results.

A single case report described the significant improvement of chronic, severe erosive pustular dermatosis of the scalp with the use of a fractional 2940-nm erbium:yttrium aluminum garnet (YAG) laser in addition to the patient's topical regimen.[31] Another case study reported the use of dehydrated human amnion/chorion membrane allograft (dHACM) to successfully treat erosive pustulosis of the scalp associated with lamellar ichthyosis.[32] A more recent case report described the successful use of oral tofacitinib in treating erosive pustular dermatosis of the scalp.[33]

Erosive pustulosis of the scalp patients should continue to be observed because carcinomas such as squamous cell carcinoma and basal cell carcinoma have been reported to arise secondarily in some cases.[34]

Surgical excision is not necessary unless carcinoma has been demonstrated on histology. In the authors’ experience, debridement of the overlying keratotic plaques should be performed with local anesthesia and curettage. Antibiotic ointment, such as mupirocin 2%, should be applied until treated regions are fully healed in order to prevent secondary infection.

Consultation with a dermatologist should be considered.

No special dietary needs are required in erosive pustulosis of the scalp.

No activity restrictions are necessary in erosive pustulosis of the scalp.

Long-term follow-up for erosive pustulosis of the scalp is indicated to monitor for possible associated morbidity, including scarring and the development of cutaneous malignancy in this high-risk population.[5] Since erosive pustulosis mainly occurs on sun-damaged skin of elderly patients, routine skin screening should be performed.

High-potency topical corticosteroids are the most commonly reported effective treatment for erosive pustulosis of the scalp. Topical tacrolimus is also reported to be useful and, when it works, may avoid the development of atrophy secondary to topical steroid therapy. For patients who do not respond to these medications, limited evidence supports trials of topical calcipotriol, topical and oral retinoids, topical dapsone, oral cyclosporine, and/or oral zinc sulfate.[5, 6, 26, 35, 36]

Fluocinonide (Fluonex)

Fluocinonide is a high-potency steroid that inhibits cell proliferation and is immunosuppressive, antiproliferative, and anti-inflammatory. It also has antipruritic and vasoconstrictive properties.

Clobetasol (Clobex)

Clobetasol is a high-potency steroid that inhibits cell proliferation and is immunosuppressive, antiproliferative, and anti-inflammatory. It also has antipruritic and vasoconstrictive properties.

Tacrolimus (Protopic)

The mechanism of action in atopic dermatitis is not known. Tacrolimus reduces itching and inflammation by suppressing the release of cytokines from T cells. It also inhibits transcription for genes that encode IL-3, IL-4, IL-5, GM-CSF, and TNF-alpha, all of which are involved in the early stages of T-cell activation. Additionally, it may inhibit the release of preformed mediators from skin mast cells and basophils and may down-regulate the expression of FCeRI on Langerhans cells. Tacrolimus can be used in patients as young as 2 years. Drugs of this class are more expensive than topical corticosteroids. It is available as ointment in concentrations of 0.03 and 0.1%. It is indicated only after other treatment options have failed.

Cyclosporine (Gengraf, Neoral, Sandimmune)

Cyclosporine is a calcineurin inhibitor that suppresses T-cell‒mediated immunity. A single case report described improvement in erosive pustulosis used at a dose of 3 mg/kg/d.

Calcipotriene (Dovonex)

Calcipotriene is a synthetic vitamin D-3 analog that regulates skin cell production and development. It inhibits epidermal proliferation, promotes keratinocyte differentiation, and has immunosuppressive effects on lymphoid cells. It is used in the treatment of moderate plaque psoriasis. Use 0.005% cream, ointment, or solution.

Tretinoin topical (Retin-A)

Tretinoin inhibits microcomedo formation and eliminates lesions present. It makes keratinocytes in sebaceous follicles less adherent and easier to remove. It is available as 0.025, 0.05, and 0.1% creams and 0.01 and 0.025% gels.

Acitretin (Soriatane)

Acitretin is a metabolite of etretinate and related to both retinoic acid and retinol (vitamin A). The mechanism of action is unknown; however, it is thought to exert its therapeutic effect by modulating keratinocyte differentiation, keratinocyte hyperproliferation, and tissue infiltration by inflammatory cells.

Zinc

Zinc is a co-factor for more than 70 types of enzymes. It plays a role in many metabolic processes. A higher requirement may be indicated in pregnancy. Use sulfate or gluconate zinc salts. Zinc sulfate 4.4 mg = 1 mg of elemental zinc. Zinc gluconate 7.1 mg = 1 mg of elemental zinc.

Dapsone topical (Aczone)

Dapsone is a topical anti-inflammatory with antineutrophilic effects. Twice daily application may produce improvement in erosive pustulosis.