Why scalp rosacea remains underestimated

In clinical practice among dermatologists, trichologists, and aesthetic medicine specialists, complaints of diffuse scalp redness, itching, burning, and associated hair thinning are common. Clinicians traditionally attribute these symptoms to seborrheic dermatitis, psoriasis, or allergic contact dermatitis; however, the review notes that a weak or absent response to corticosteroids characterizes scalp rosacea. One of the underestimated causes of persistent inflammation is scalp rosacea, also known in the literature as «red scalp disease» [1]. Insufficient awareness among specialists and the lack of agreed clinical criteria lead to delayed diagnosis and inadequate treatment regimens.

In 2026, a team of authors published a narrative review in the journal Dermatology and Therapy summarizing current knowledge on the etiopathogenesis, clinical picture, trichoscopic criteria, histopathology, and management algorithms for patients with rosacea of the scalp [1]. The researchers systematized scattered literature data to help practitioners navigate the differential diagnosis of complex cases of erythematous scalp lesions.

Clinical picture and possible mechanisms

The clinical picture of scalp rosacea consists of diffuse erythema, dry pityriasiform scaling, telangiectasias, and sparse papules and pustules usually not associated with follicles. Patients predominantly report itching and burning (stinging), worsened by heat, sun exposure, or irritating products. The most important clinical feature is that scalp erythema may coexist with classic facial rosacea manifestations or develop completely in isolation, masquerading as other dermatoses. In addition, patients often report increased hair loss, which prompts them to consult trichologists and skincare specialists.

The disease's pathogenetic links are not yet fully understood and are largely extrapolated from data on facial rosacea. Researchers hypothesize an interaction among genetic predisposition, innate immune dysregulation, and neurovascular changes. In response to external stimuli, keratinocytes release cathelicidin, which is proteolytically converted into LL-37, promoting macrophage activation and inflammatory signaling pathways. Microscopic mites of the genus Demodex, predominantly Demodex folliculorum, play a notable role. The scalp, with its abundance of pilosebaceous follicles, may serve as a mite reservoir. In one study cited in the review, 35% of Demodex-positive scalp biopsies were found in patients with rosacea versus 0% in the control group, and the difference was statistically significant (p = 0.033) [2].

Trichoscopy and differential diagnosis

Trichoscopy has been a significant step forward in non-invasive diagnosis. In a pilot retrospective study of 21 patients with histologically confirmed scalp rosacea, the authors characterized specific dermoscopic markers in detail [3]. Among the identified features:

• linear vessels with short thin branches resembling caterpillar hairs (caterpillar hair vessels) — in 86% of examined patients;
• thin arborizing vessels — in 76%;
• polygonal rhomboid vascular structures — in 71%;
• thick arborizing vessels — in 67%;
• perifollicular scaling — an early and persistent sign;
• tubular scales — in 38%;
• signs associated with the presence of Demodex mites — in 29% of patients.

Differential diagnosis of scalp involvement includes several diseases:

• Seborrheic dermatitis: itching and greasy yellowish scales.
• Psoriasis: erythematous plaques with silvery-white scaling; lesions may extend beyond the hairline.
• Contact dermatitis: itching and symptom onset after contact with a new product or other potential irritant; changes may spread to the hairline, ears, and neck.
• Lichen planopilaris: diffuse erythema, hair thinning, and trichodynia — pain or unpleasant sensations in the scalp area.
• Discoid lupus erythematosus: scarring alopecia, pigmentary changes, follicular atrophy, and plaques in photodistributed areas.
• Folliculitis decalvans: perifollicular pustules, yellowish crusts, and tufts of hairs emerging from a single follicular opening.

In unclear cases, the review authors recommend performing a biopsy under dermoscopic control. Histologically, early stages show interstitial edema and marked ectasia of dermal capillaries. In the advanced stage, perivascular and perifollicular lymphohistiocytic infiltrates form around the infundibulum and isthmus of the follicle, often with visualization of Demodex mites in the follicular lumen. The most important histopathological feature is the absence of epithelial destruction, sebaceous gland atrophy, and fibrosis, underscoring the disease's non-scarring nature.

Treatment approaches

Because standardized international clinical protocols for treating scalp rosacea have not yet been established, therapeutic approaches combine topical and systemic interventions with proven efficacy in facial rosacea [1].

First-line systemic treatment includes tetracycline-group drugs due to their pronounced anti-inflammatory action: lymecycline at 150–300 mg/day, doxycycline at 40–200 mg/day, or minocycline at 100 mg/day for 4 to 8 weeks, followed by gradual tapering to the minimum effective dose.

For topical therapy of the scalp, lotions or solutions of metronidazole 0.75–1%, ivermectin 0.5–1%, or azelaic acid solutions 15–20% are prescribed.

In refractory cases, oral ivermectin at 200 mcg/kg body weight with a repeat dose after 7–14 days or low-dose systemic isotretinoin (0.1–0.2 mg/kg/day) may be considered.

Limitations and practical takeaways

The key limitation remains the lack of agreed diagnostic criteria and therapeutic algorithms: no consensus on scalp rosacea has been reached to date. The authors also note that no specific studies of the pathogenetic mechanisms of scalp rosacea per se have been conducted, so current concepts are largely extrapolated from data on facial rosacea. Androgenetic alopecia is considered a possible predisposing factor; however, in one of the studies cited, no clear association with it or with ultraviolet exposure was found.

For dermatologists and skincare specialists, understanding the features of scalp rosacea creates opportunities to prevent unnecessary aggressive interventions and prescribe targeted anti-inflammatory therapy. Patients with persistent scalp erythema should avoid triggers such as corticosteroids (topical and systemic), sun exposure, hot beverages, and potential contact irritants. They should adhere to gentle scalp cleansing and photoprotection. Proper differentiation of rosacea from scarring dermatoses allows reassuring the patient about the prognosis: temporary increased hair loss is possible, but scarring alopecia does not develop.

Thus, scalp rosacea is an independent clinical problem that requires high diagnostic vigilance from aesthetic medicine specialists. A comprehensive assessment of itching and burning complaints, combined with a trichoscopic search for characteristic vascular structures, allows an early preliminary diagnosis. Excluding scarring processes with trichoscopy or biopsy confirms a favorable prognosis for hair density. According to the review, timely prescription of systemic tetracyclines and topical anti-inflammatory agents is the most consistently effective approach: erythema and symptom severity decrease during treatment.

References

1. Olvera-Rodríguez V., Pampaloni F., Sechi A., Starace M.V.R. Scalp rosacea: current evidence. Dermatol Ther (Heidelb) 2026; 16: 4293–4303.
2. Trave I., Salvi I., Schiavetti I. et al. Presence of Demodex spp. on the face and scalp in patients affected by papulopustular rosacea of face. Ital J Dermatol Venerol 2024; 159(4): 425–429.
3. Lin D., Martins G., Sanz J. et al. A pilot retrospective study on trichoscopy of 21 cases of rosacea of the scalp. J Am Acad Dermatol 2023; 88(4): 898–900.