Abstract
Introduction
Red scalp disease or scalp rosacea, an inflammatory dermatosis, is frequently misdiagnosed as scarring alopecia due to nonspecific trichoscopic findings and limited case reports. While facial rosacea is well-documented, rosacea affecting extrafacial sites, such as the scalp, remains underrecognized. Accurate diagnosis is crucial to avoid unnecessary treatments and to establish an appropriate prognosis.
Case Report
A 70-year-old male with an asymptomatic red scalp for 1 year, unresponsive to topical treatments, presented to our clinic. Examination revealed diffuse erythema with papules and pustules. Trichoscopy showed vascular polygons, “caterpillar hair” vessels, linear arterial branching, and hairpin vessels. Diagnosis of scalp rosacea was made, and significant improvement was observed after 2 months of oral tetracycline therapy.
Discussion/Conclusion
Red scalp disease is characterized by diffuse erythema, inflammatory lesions, and vascular changes. Patients often exhibit mild facial photosensitivity but may not show prominent facial rosacea symptoms. Distinct trichoscopic patterns can assist in accurate diagnosis. Early recognition and treatment with systemic antibiotics, such as tetracyclines, are crucial to prevent progression to more severe inflammation. Increased awareness among dermatologists and trichologists is essential to enhance the diagnosis and management of this condition.
Keywords: Red scalp disease, Scalp rosacea, Scarring alopecia, Non-scarring alopecia, Inflammatory alopecias
Established Facts
Scalp rosacea is an underdiagnosed presentation of rosacea, often misdiagnosed as scarring alopecia due to overlapping clinical and trichoscopic features.
Most patients with scalp rosacea may not exhibit the typical facial symptoms of rosacea.
Trichoscopic examination of the scalp typically reveals nonspecific findings such as peripilar scaling and vascular changes, which can be seen in other scalp conditions.
Novel Insights
The identification of specific trichoscopic patterns, such as “caterpillar hair” vessels and polygonal structures, provides valuable diagnostic clues that can help differentiate RDS from other inflammatory scalp conditions.
Early diagnosis and treatment with systemic antibiotics such as tetracyclines can effectively manage symptoms and prevent progression to more severe inflammation.
Enhanced awareness among dermatologists and trichologists is essential for early diagnosis and effective treatment of scalp rosacea.
Introduction
Red scalp disease (RDS) or scalp rosacea is an inflammatory dermatosis that is frequently misdiagnosed as scarring alopecia, mainly due to nonspecific trichoscopic findings and limited case reports. Accurate diagnosis is essential to avoid unnecessary treatments and to establish an appropriate prognosis for both the short and long term. While facial rosacea is a well-documented and prevalent condition, rosacea affecting extrafacial sites, such as the scalp, remains poorly defined [1]. Trichoscopy, although helpful, often reveals nonspecific findings such as peripilar scaling, indicative of active disease. However, unlike some other scalp conditions, chronic scalp rosacea does not lead to scarring alopecia or permanent hair loss. Early diagnosis remains essential to manage symptoms and prevent the development of more severe inflammatory lesions [2].
Case Report
A 70-year-old male, with an unremarkable medical history, presented to our trichology clinic with a 1-year history of an asymptomatic red scalp. Previous treatment with multiple topical medications yielded no clinical improvement. Upon examination, diffuse erythema accompanied by numerous papules and pustules was observed across the scalp (Fig. 1). Trichoscopy revealed vascular polygons, “caterpillar hair” vessels, linear arterial branching, hairpin vessels (Fig. 2), peripilar scaling, follicular plugs, and pustules (Fig. 3). Based on these findings, a diagnosis of scalp rosacea was made. The patient demonstrated marked clinical improvement following 2 months of oral tetracycline treatment.
Fig. 1.
Clinical examination revealed confluent erythema, along with papules, pustules, and extensive crusting on the vertex of the scalp.
Fig. 2.
Hairpin vessels, “caterpillar hair” vessels (arrows), and diffuse erythema.
Fig. 3.
Pustules, follicular plugs, and crusts.
Discussion
RDS is an underrecognized condition marked by diffuse erythema, inflammatory papules, pustules, and vascular changes. Clinically, patients may present with a red, itchy, or burning scalp, often accompanied by telangiectasia and, occasionally, follicular pustules. Notably, most patients do not exhibit classic facial rosacea symptoms, except for mild facial photosensitivity, which is typically only noted upon direct questioning. These symptoms can persist for months to years and significantly impact quality of life, especially in severe cases [3].
Trichoscopy, while valuable, often reveals findings overlapping with other scalp conditions. Common trichoscopic features such as vascular polygons, linear branching vessels, hairpin vessels, peripilar scale, and follicular plugs are not exclusive to RDS and may contribute to misdiagnosis. A recent study of 21 biopsy-proven RSD cases identified distinct vascular patterns, including “caterpillar hair” vessels and polygonal structures, in 86% and 71% of cases, respectively. These findings, aligned with histological evidence of dilated, geometrically shaped capillaries, aid in differentiating RSD from conditions like seborrheic dermatitis and psoriasis [4].
Dermoscopy can effectively identify specific signs of Demodex folliculorum infestation, such as demodex tails, dilated follicular openings, and dilated blood vessels, which strongly correlate with positive mite tests [5]. While these findings are commonly associated with demodicosis and facial rosacea, they should also be considered in red scalp disease, as Demodex mites are often observed in histopathological examinations of this condition.
Diagnosing diffuse scalp erythema is challenging due to the variety of potential causes and different thrichoscopic findings, including psoriasis, seborrheic dermatitis, head and neck atopic dermatitis, head and neck dermatitis induced by dupilumab, contact dermatitis, diffuse lichen planopilaris, dermatomyositis, discoid lupus erythematosus, and scalp rosacea (Table 1). While histological analysis remains the gold standard, trichoscopy combined with clinical examination often provides sufficient diagnostic clarity [6, 7]. Histopathological findings of RDS include dilated venules and dermal edema, with a sparse perivascular lymphocytic infiltrate. As the condition advances, there is an increase in perivascular and perifollicular infiltration, including neutrophils, with a tendency toward granuloma formation in papular lesions. Pustular lesions contain intrafollicular neutrophils. Demodex mites are frequently identified within the follicular infundibulum [8, 9].
Table 1.
| Etiology | Trichoscopic findings |
|---|---|
| Psoriasis | Silver-white scaling |
| Regularly distributed dotted vessels or twisted red loops | |
| Punctate hemorrhages | |
| Seborrheic dermatitis | Yellowish-white scaling |
| Thin arborizing vessels | |
| Contact dermatitis | Yellow exudate and arborizing vessels |
| Lichen planopilaris | Perifollicular scaling |
| Erythema with the lack of follicular openings | |
| Dermatomyositis | Tortuous and arborizing vessels |
| Interfollicular and perifollicular pigmentation | |
| Head and neck dermatitis induced by dupilumab | Erythema, perifollicular scale, and interfollicular scale |
| DLE | Follicular keratotic plugs, arborizing vessels, and perifollicular scaling |
| Absent follicular openings and white structureless areas are indicative of scarring DLE | |
| Red scalp disease | Vascular polygons, “caterpillar hair” vessels, linear branching vessels, hairpin vessels, perifollicular scale, and follicular plugs |
DLE, discoid lupus erythematosus.
Treatment with oral tetracyclines has proven effective for RDS, especially when topical treatments have failed. Given its inflammatory nature, systemic antibiotics such as tetracyclines are essential for symptom reduction and preventing progression to more significant inflammation [11, 12]. Increased awareness among dermatologists and trichologists is necessary to ensure timely diagnosis and appropriate management.
Conclusions
RSD is likely underreported and frequently misdiagnosed due to its nonspecific clinical and trichoscopic features, which often overlap with other inflammatory scalp conditions such as seborrheic dermatitis and psoriasis. Despite its similarities to more common scalp disorders, RDS presents with distinct vascular patterns, including “caterpillar hair” vessels and polygonal structures, which can serve as valuable diagnostic markers. Early recognition and accurate diagnosis are crucial for effective management as prompt treatment with systemic antibiotics, like tetracyclines, can significantly reduce symptoms and prevent further complications. Increased awareness and education among dermatologists and trichologists are essential to improve diagnosis, reduce misdiagnosis, and ensure that patients receive timely, appropriate care to prevent unnecessary interventions.
Statement of Ethics
Ethical approval is not required for this study in accordance with local or national guidelines. Written consent was obtained from the patients at the time for publication of this case report and any accompanying images.
Conflict of Interest Statement
All authors have no conflict of interest to disclose.
Funding Sources
No funding was received from any source during the preparation of this manuscript.
Author Contributions
Daniel Asz-Sigall and Alejandra Segarra wrote the original draft in support with Sofía Olvera-Lerma. Eduardo Corona-Rodarte and Luis Enrique Cano-Aguilar ensured scientific accuracy of the manuscript and were responsible for the design and critical revision of the manuscript. All authors approved the final version of the manuscript for submission.
Funding Statement
No funding was received from any source during the preparation of this manuscript.
Data Availability Statement
All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.