Inflammatory Tinea Capitis Mimicking Dissecting Cellulitis in a Healthy Woman

Abstract

Introduction

Inflammatory tinea capitis (TC) is uncommon in adults.

Case Presentation

A 29-year-old healthy woman presented with a 2-year history of scalp alopecia with purulent discharge. Clinical, trichoscopic, and histological features and the negativity of a first fungal sampling were consistent with the diagnosis of dissecting cellulitis of the scalp. A second mycological examination guided by trichoscopy was carried out, showing tinea endothrix. Fungal culture isolated trichophyton violaceum. The patient was treated with terbinafine with complete healing.

Conclusion

The diagnosis of adult TC is challenging, mainly the inflammatory form. An exhaustive trichoscopic examination of all alopecic plaques may help make a rapid diagnosis and provide a guide to the mycological examination.

Established Facts

• Tinea capitis is uncommon in adults. It affects mainly postmenopausal women with predisposing factors.

• The mycological examination is the gold standard method of the diagnosis of tinea capitis.

• Irregularly distributed 3-dimensional yellow dots are highly suggestive of active dissecting cellulitis of the scalp.

Novel Insights

• Inflammatory tinea capitis can affect immunocompetent adults.

• Irregularly distributed 3-dimensional yellow dots can be a sign of inflammatory tinea capitis.

• An exhaustive trichoscopy increases the sensibility of the mycological examination.

Introduction

Tinea capitis (TC) is a common fungal infection of the scalp in children. Adult TC is less frequent. This is explained by the fungistatic properties of sebum in adults [1]. It is characterized by a clinical polymorphism and atypia responsible for a long course and delayed diagnosis. Clinical features depend on the etiological agent and on the immune status of the host [2]. Inflammatory TC is an uncommon form and is even rarer in postpubertal patients. It is explained by an intense hypersensitivity reaction to the dermatophytic infection [3]. The mycological examination is the gold standard method of diagnosis. We report the case of an immunocompetent woman presenting an inflammatory TC diagnosed by trichoscopy.

Case Report

A 29-year-old woman presented with a 2-year history of scalp alopecia with purulent discharge. She was treated with many antibiotics, including doxycycline without improvement. She was otherwise healthy and has never been treated with immunosuppressive drugs or topical corticosteroids. Her last pregnancy was 5 years ago. Clinical examination showed painful and boggy nodules with purulent discharge and multiple alopecic, erythematous crusted, and purulent plaques on the vertex and occipital scalp (Fig. 1a). There was no tufted hair nor eyelash and eyebrow damage. Trichoscopy revealed red dots, irregularly distributed 3-dimensional (3D) yellow dots, hemorrhagic crusts, and amorphous reddish areas (Fig. 2a). Hair fungal and bacteriological sampling were negative. Punch biopsy showed a perifollicular polymorphic inflammatory infiltrate, rich in neutrophils forming micro-abscesses. Direct immunofluorescence was negative. The diagnosis of dissecting cellulitis of the scalp (DCS) was made. The patient was started on isotretinoin. During clinical monitoring, trichoscopic examination revealed, in a small area on the vertex, broken hairs, comma hairs, and corkscrew hairs (Fig. 2b). A second mycological examination guided by trichoscopy was carried out. KOH examination showed a tinea endothrix. Fungal culture isolated trichophyton violaceum. There were no cases of TC in the family. The patient was treated with terbinafine (250 mg daily) for 1 month with complete healing, but she still has some plaques of scarring alopecia (Fig. 1b).

Fig. 1.

a Multiple erythematous, purulent, and crusted plaques with scarring alopecia. b Some areas of scarring alopecia after treatment.

Fig. 2.

a Trichoscopy showing perifollicular scales (red arrow), hemorrhagic crusts (white arrow), 3D yellow dots (black arrow), red dots (blue circle), amorphous structureless area (white star). b Trichoscopy showing comma hair (red circle), broken hair (blue circle), corkscrew hair (yellow arrows), and inter- and perifollicular scales (green circle).

Discussion

TC is very rare in adults and affects mainly postmenopausal women, at the occasion of the involution of sebaceous glands. The most reported predisposing factors are diabetes, anemia, corticosteroid therapy, malignancy, transplantation, HIV infection, immunosuppression, and hormonal changes (pregnancy and menopause) [1, 2]. Our patient had no medical history, and her only medications were antibiotics prescribed for her alopecia.

The causative agent of adult TC can vary depending on the geographical area. Trichophyton violaceum is the most common responsible agent in Tunisia, Egypt, and China [2, 4]. Microsporum canis is the main pathogen in Italy and Belgium [4, 5]. Trichophyton tonsurans is predominant in USA and France [4].

The most common presentations of adult TC are alopecic plaques with or without inflammation, scales, pustules, truncated hair, sensitive inflammatory nodules, and normal looking hair without tensile strength [2]. This polymorphic and atypical clinical presentation is responsible for diagnostic delays. The duration of the disease before the mycological confirmation ranges from 20 days to 30 years [4]. It was 2 years in our case. The most common presumptive initial diagnosis is seborrheic dermatitis followed by bacterial folliculitis, allergic contact dermatitis, and psoriasis [6]. Several cases of adult inflammatory TC were misdiagnosed as DCS, and the mycological examination has always led to the correct diagnosis [7]. In our case, a first negative culture made the diagnosis challenging. A second examination performed in the plaque showing characteristic dermoscopic features of TC confirmed the diagnosis.

Broken hairs, black dots, perifollicular, and interfollicular scales are common in TC. They can also be found in other scalp diseases. The majority of the plaques in our patient showed scales, erythema, irregularly distributed 3D yellow dots, and structureless areas leading initially to the diagnosis of DCS. Yellow dots are seen in several diseases of the scalp. They correspond to dilated follicular infundibulum filled with keratotic material. The 3D appearance is highly suggestive of DCS and is not observed in other cicatricial or non-cicatricial forms of alopecia [8]. That is why we can discuss the possibility of a fungal infection in a patient with DCS, but the complete recovery with terbinafine has excluded this hypothesis. Thus, yellow dots in our case correspond to crusts. However, corkscrew hairs, comma hairs, barcode-like hairs, zigzag hairs, and bent hairs are the most characteristic signs of TC. Their specificity is about 100%, but their sensitivity ranges from 7% to 50% which explains the presence of corkscrew hairs and comma hairs in only one limited area of the scalp in our patient [9].

The diagnosis of adult TC is challenging, mainly the inflammatory form. We believe that an exhaustive trichoscopy of all alopecic plaques may help make a rapid diagnosis and provide a guide to the mycological examination.

Statement of Ethics

Written informed consent was obtained from the patient for publication of this case report and any accompanying images. Ethical approval is not required for this case report in accordance with local guidelines.

Conflict of Interest Statement

The authors have no conflict of interest to disclose.

Funding Sources

The authors have received no funding.

Author Contributions

Dr. Faten Rabhi and Dr. Dorsaf Elinkichari have given their contribution to manuscript conception and writing. Dr. Latifa Mtibaa and Bouthaina Jemli have analyzed mycological data. Prof. Kahena Jaber and Prof. Raouf Dhaoui have given their contribution in reviewing the manuscript for important intellectual content.

Funding Statement

The authors have received no funding.

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.