Erosive Pustular Dermatosis
Erosive pustular dermatosis of the scalp is a rare, chronic inflammatory skin condition. It is marked by sterile pustules, shallow oozing erosions and thick, adherent crusts on scalp skin that has become thin and atrophic. It is seen most often in older adults with long-standing sun damage (actinic keratosis) or a history of scalp injury or surgery.
Although the pus and crusting can look like a severe infection, the condition belongs to the group of sterile neutrophilic dermatoses:
- Chronic sun damage and atrophy: years of ultraviolet (UV) exposure break down elastic fibers and thin both the epidermis and dermis of the scalp. This atrophic skin repairs itself poorly, and the tissue around hair follicles becomes prone to spontaneous inflammation.
- Sterile neutrophilic inflammation: the affected skin mounts an intense inflammatory reaction with large numbers of neutrophils, yet cultures of the pus show no primary bacterial or fungal pathogen (at most, normal skin flora growing alongside).
- Trauma-induced flares (Koebner-like phenomenon): local procedures such as excision of skin lesions, cryotherapy, photodynamic therapy (PDT) or skin grafting, and even minor injuries like scratches or bumping the head, can breach the skin barrier and set off erosive, pustular inflammation that persists for months or years.
At Haute-Derma, we recognize erosive pustular dermatosis of the scalp as a diagnostic challenge that is easily mistaken for a severe bacterial or fungal infection. Our approach focuses on avoiding unnecessary invasive procedures (which worsen erosions through the Koebner phenomenon), quickly calming the sterile inflammation with topical immunomodulating treatment, and protecting the fragile, atrophic skin against relapse.
Clinical Features and Trichoscopy Findings
The condition usually affects older people (over 60), especially bald men with thinned scalp skin and women with heavily sun-damaged skin:
- Typical Sites:
- The bald crown and temples: areas exposed directly and constantly to the sun.
- How the Lesions Evolve:
- Early stage: small, superficial pustules appear, scattered or grouped into patches, on red, thin scalp skin with visible dilated small vessels.
- Erosion and crusting: the pustules soon break open, leaving shallow erosions that keep oozing. The fluid dries into layers of very thick, firmly stuck yellow-gray or gray-brown crust. Lifting the crust exposes raw, bright red skin that bleeds and is very painful.
- Late stage: over time the disease leads to scarring hair loss (cicatricial alopecia), leaving smooth, shiny, hardened skin with no remaining hair follicles.
- Trichoscopy (Scalp Dermoscopy) Findings:
- Atrophic skin with telangiectasia: the epidermis looks thin and waxy, like paper, with a visible network of linear, looped or branching vessels.
- Sticky yellow-brown crusts: broad masses of keratotic crust covering the eroded areas.
- Loss of follicular openings: the hallmark of scarring alopecia, with no trace of follicular openings left in the fibrotic areas.
Our Approach and Treatment Options at Haute-Derma
The main goals in managing erosive pustular dermatosis of the scalp are to suppress the sterile inflammation, remove crusts gently and strictly avoid any further mechanical injury.
Controlling Inflammation With Topical Immunomodulators
The neutrophil-driven inflammation needs to be brought under control with potent topical anti-inflammatory and immunomodulating agents.
- Potent topical corticosteroids: agents such as clobetasol propionate quickly reduce oozing, settle the pustules and halt the spread of erosions during the acute phase.
- Topical calcineurin inhibitors: tacrolimus or pimecrolimus is an excellent alternative for long-term maintenance, controlling inflammation without adding steroid-induced atrophy to scalp skin that is already thin and fragile.
Systemic Treatment to Suppress Pustule Formation
Used when lesions are extensive, respond poorly to topical treatment or flare frequently.
- Oral neutrophil-inhibiting drugs: oral dapsone or colchicine blocks the recruitment and activation of neutrophils in the skin, helping to control sterile pustule formation.
- Oral retinoids: low-dose isotretinoin or acitretin helps normalize keratinocyte differentiation, reduces inflammation and improves the quality of the atrophic scalp skin.
Gentle Skin Care and Crust Removal
Removing crusts correctly is essential so that topical medicines can actually reach the lesions.
- Soaking to soften crusts: daily compresses with saline or a mild antiseptic solution soften the hard crust so it lifts away on its own, without bleeding or scraping.
- No invasive procedures: curettage, cryotherapy, electrocautery and surgery on affected skin are contraindicated, because the Koebner phenomenon can trigger a more severe erosive, pustular flare.
Telling Apart Erosive, Crusting Scalp Conditions
| Erosive pustular dermatosis of the scalp | Severe seborrheic dermatitis | Folliculitis decalvans (FD) |
|---|---|---|
| Sterile pustules, shallow erosions, thick yellow-gray crusts. | Red patches with greasy yellow scale; no erosions. | Pustules around hair follicles, sticky crusts, tufted hairs. |
| Thin, chronically sun-damaged, balding scalp. | Oily skin with excess sebum. | Normal scalp, or thickened and inflamed with scarring. |
| Sterile inflammation plus trauma or UV exposure (Koebner). | Malassezia yeast plus excess sebum. | Hypersensitivity reaction to Staphylococcus aureus (S. aureus). |
| Extensive, permanent atrophic scarring alopecia. | No scarring. | Progressive patchy scarring alopecia, hypertrophic or atrophic. |
