Alopecic and Aseptic Nodules of the Scalp: A New Entity or a Minor Form of Dissecting Cellulitis?

Since the original report in 1992 and revised nomenclature in 2009, pseudocysts of the scalp and alopecic and aseptic nodules of the scalp (AANS), respectively, have been regarded as a new entity that is rare and not understood in its pathogenesis. We observed 26 cases of AANS. Except for the extent and severity of disease, we found no single feature that justifies distinguishing AANS as a nosologic entity in its own right from dissecting cellulitis of the scalp (DCS). The scarring alopecias represent a diverse group of disorders with the potential of permanent destruction of the pilosebaceous unit and hair loss. Within the maze of varied conditions leading to scarring alopecia, the most important is to keep a neat nosologic classification in mind, based both on morphology and a pathogenic understanding. We believe that AANS represents a minor form of DCS, so far predominantly observed in patients of non-African origin, and therefore, is a disease of follicular occlusion with a favorable prognosis. Copyright:

“As the true object of education is not to render the pupil the mere copy of his preceptor, it is rather to be rejoiced in, than lamented, that various reading should lead him into new trains of thinking.”

INTRODUCTION

In 1992, Iwata et al. originally reported 19 Japanese patients with pseudocysts of the scalp with inflammatory granulation tissue presenting as solitary painful subcutaneous tumor associated with alopecia.[1] It was not until 1998 that Chevallier reported three cases of noninfectious abscesses of the scalp with alopecia on the occasion of the French Federation of Continuing Medical Education in Dermatology and questioned whether it represented a new nosologic entity.[2] In 2005, Tsuruta et al. reported four additional cases of the so-called pseudocysts of the scalp under the assertion that there were no reports of such lesions in the Western literature for lack of familiarity with the French language.[3] Ultimately, Abdennader and Reygagne coined the term alopecic and aseptic nodules of the scalp (AANS) for the condition in a retrospective review of 18 cases seen over a period of 12 years at the Saint-Louis Hospital in Paris.[4] Subsequently, Abdennader et al. reported a prospective study of 15 cases of AANS and demonstrated that the disorder affected predominantly young men of Caucasian origin.[5] The main location of the nodules was occipital. Microbiological cultures of material from the puncture were negative. The histopathology showed a deep granulomatous inflammation. Pseudocysts were not always present. The condition responded well to oral doxycycline therapy with the recovery of hair. Subsequent single case reports and case series did not add any new insight of pertinence to the nomenclature and nosology of the condition,[678910111213141516] including Heymann's latest comment in Dermatology World Insights and Inquiries.[17] Under the line, the authors state that the condition is rare, probably underreported, and its etiopathogenesis poorly understood.

The condition received its designation based on the clinical presentation with either one or few dome-shaped, firm, fluctuating, or soft, alopecic nodules of the scalp on the vertex or occipital area [Figure 1] that when punctured drain a sterile purulent or blood-tinged fluid. Histopathology shows a nonspecific mixed inflammatory infiltrate in the deep dermis; however, a granulomatous infiltrate with multinucleated foreign-body giant cells and pseudocyst formation may be found.[510] Dermoscopic features are black and yellow dots, fine vellus hairs, and broken hair shafts, with none of these being pathognomonic for the condition.[11] Bourezane and Bourezane reported the “Eastern pancake sign” referring to dilated follicular orifices and comedo-like structures [Figure 2a and b].[18] Ultrasonographic studies demonstrated well-defined hypoechoic or anechoic subcutaneous nodular lesions.[11] The course of the disease is chronic relapsing with partial or total regrowth of the hair. Doxycycline 100–200 mg/d for 8–12 weeks was the most used treatment, followed by intralesional triamcinolone acetonide injections.[19]

Figure 1

Clinical presentation of alopecic and aseptic nodules of the scalp. Dome-shaped alopecic nodules on the scalp vertex of a Caucasian man

Figure 2

The eastern pancake sign-on dermoscopy: (a) Eastern pancake, (b) dilated follicular orifices and comedo-like structures

CASE OBSERVATIONS

At our hair disease clinic, we observed 26 cases in 10 years with the all-inclusive features of AANS [Table 1]. Again, the majority of our patients were male Caucasians, and the age ranged from 18 to 48 years. The patients responded well to either oral doxycycline or low-dose isotretinoin, associated with intralesional triamcinolone acetonide 20–40 mg/mL, with complete or partial regrowth of hair. In contrast to the former authors, we interpreted the condition as the minor manifestation of dissecting cellulitis of the scalp (DCS). The condition seemed to us obvious to the extent that we did not find it necessary to perform biopsies in our cases.

Table 1

Patient characteristics, treatment regimen, and outcome

Patient number	Sex	Age	Ethnicity	Lesions	Treatment	Outcome
1	Male	44	Caucasian	Single	Oral isotretinoin 20 mg	Unknown
2	Male	39	North African	Multiple	Surgical excision	Complete remission
3	Male	46	Caucasian	Multiple	Topical clindamycin 1%, oral zinc gluconate 30 mg	Unknown
4	Male	41	Caucasian	Multiple	Oral isotretinoin 10 mg, topical clindamycin 1%, oral zinc gluconate 30 mg	Unknown
5	Male	27	Caucasian	Multiple	Oral isotretinoin 20 mg, oral zinc gluconate 30 mg, intralesional triamcinolone acetonide	Partial remission
6	Male	36	Caucasian	Multiple	Intralesional triamcinolone acetonide	Complete remission
7	Male	30	Caucasian	Multiple	Oral doxycycline 100 mg	Complete remission
8	Male	38	Caucasian	Multiple	Oral isotretinoin 20 mg	Complete remission
9	Male	40	Caucasian	Single	Topical clindamycin 1%	Complete remission
10	Male	29	Caucasian	Single	Oral isotretinoin 20 mg	Unknown
11	Male	44	Caucasian	Multiple	Intralesional triamcinolone acetonide	Unknown
12	Male	18	Asian	Multiple	Oral doxycycline 100 mg, intralesional triamcinolone acetonide	Relapsing course
13	Male	40	Caucasian	Multiple	Lymecycline 300 mg	Complete remission
14	Male	39	Caucasian	Multiple	Topical clindamycine 1%, oral zinc gluconate 30 mg	Unknown
15	Male	33	Caucasian	Multiple	Topical clindamycine 1%, oral zinc gluconate 30 mg	Unknown
16	Male	41	Caucasian	Multiple	Topical erythromycin	Unknown
17	Male	27	Caucasian	Single	Topical clindamycin 1%, oral zinc gluconate 30 mg	Unknown
18	Male	30	Caucasian	Multiple	Oral isotretinoin 40 mg, intralesional triamcinolone acetonide	Complete remission
19	Male	32	Caucasian	Multiple	Intralesional triamcinolone acetonide, topical clindamycin 1%	Complete remission
20	Male	52	Caucasian	Single	Oral doxycycline 100 mg, intralesional triamcinolone acetonide	Partial remission
21	Male	48	North-African	Multiple	Oral zinc gluconate, topical clindamycin 1%, intralesional triamcinolone acetonide	Total remission
22	Male	40	North-African	Multiple	Oral doxycycline 100 mg, intralesional triamcinolone acetonide	Total remission
23	Male	26	Caucasian	Multiple	Surgical excision, oral doxycycline 100 mg, intralesional triamcinolone acetonide	Relapsing course
24	Male	37	Caucasian	Multiple	Oral doxycycline 100 mg, intralesional triamcinolone acetonide	Total remission
25	Male	30	Caucasian	Multiple	Oral doxycycline 100 mg, intralesional triamcinolone acetonide	Total remission
26	Male	24	North-African	Multiple	Oral doxycycline 100 mg, intralesional triamcinolone acetonide	Total remission

DISCUSSION

DCS, also known as perifolliculitis capitis abscedens et suffodiens, or Hoffmann's disease, is a distinct dermatological disease potentially leading to scarring alopecia. It most probably occurs because of follicular occlusion through hyperkeratosis, having the same pathomechanism as acne conglobata and hidradenitis suppurativa. These dermatoses may be associated, although isolated scalp disease occurs more frequently. Most of those affected are young males of African origin. Deep inflammatory nodules develop on the occipital scalp or vertex and evolve to extensive confluent boggy plaques with sinus tract formation, particularly in patients of African origin. Dermoscopic findings in DCS include broken hair, short regrowing hairs, black dots, follicular pustules, peri- and interfollicular erythema, and empty follicular openings.[20] What is characteristic for the histopathologic picture of the disease is the deep inflammatory infiltrate placed at the reticular dermis or hypodermic level. The initial perifolliculitis evolves toward forming profound abscesses and the destruction of follicles with granuloma formation, usually lymphoplasmacytic and accompanied by multinucleated foreign-body giant cells that may be related to denuded hair fragments.[21]

Indeed, due to peculiarities of hair anatomy and hair grooming habits, environmental factors, and maybe genetic factors,[22] a number of inflammatory scalp conditions tend to be more common or severe in patients of African origin, such as folliculitis keloidalis nuchae, central centrifugal cicatricial alopecia, discoid lupus erythematosus,[23] and DCS.

Therefore, we do not consider AANS a disease entity in its own right but a disease manifestation of DCS at the minor end of its clinical spectrum. Apart from the lesser degree of severity and extent, AANS does not present any features distinct from DCS, except for those related to the severity and extent of disease and ethnicity [Table 2]. With respect to pathogenesis, in fact, the dermoscopic feature of comedo-like structures suggests the potential role of follicular occlusion.[11] Finally, also treatment is the same, with oral doxycycline or low-dose isotretinoin[24] associated with intralesional triamcinolone acetonide being effective. While large-scale surgical excision in combination with reconstructive surgery may be necessary in severe cases of DCS, surgery is not warranted in AANS because of its favorable prognosis [Figure 3a and b].

Table 2

Features of alopecic and aseptic nodules of the scalp and dissecting cellulitis of the scalp

Disease	Sex	Ethnicity	Course	Scarring or non-scarring	Number of nodules	Culture	Trichoscopy	Localization	Histopathology	Treatment
AANS	Mostly young males	Mostly seen in Asian and Caucasian patients	Self-limited (3 months) or chronic	Non-scarring	Single or multiple tender nodules	Negative (sterile)	Black and yellow dots, fine vellus hair, broken shafts, “comedo-like” structures	Vertex, occiput, parietal, frontal	Mixed inflammatory infiltrate in the deep dermis (neutrophils, lymphocytes, abundant plasma cells, multinucleated foreign body giant cells, granulomatous reaction.	Doxycycline, low dose isotretinoin, intralesional corticosteroids
DC	Mostly young males	Mostly African, can also affect Asian, Caucasian, Hispanic	Chronic	Non-scarring or scarring (late stage)	Single or multiple; severe cases may exhibit interconnected abcesses	Negative in most cases; few cases positive to Staphylococcus	Black and yellow dots, fine vellus hair, broken shafts, “comedo-like” structures	Vertex, occiput, parietal, frontal	Early-stage: moderately dense, lymphocytic, perifollicular inflammation surrounding the lower half of the follicle; Advanced stages: perifollicular and mid to deep dermis abscesses with neutrophils, lymphocytes, abundant plasma cells, granulation tissue, and fibrosis may be seen. Fully developed lesions show suppurative and granulomatous inflammation.	Oral antibiotics, low dose isotretinoin, intralesional corticosteroids

AANS – Alopecic and aseptic nodules of the scalp; DCS – Dissecting cellulitis of the scalp

Figure 3

Favorable prognosis (a) before and (b) after treatment with low-dose oral isotretinoin and intralesional triamcinolone acetonide

SUMMARY AND CONCLUSIONS

The scarring alopecias represent a diverse group of disorders with the potential for permanent destruction of the pilosebaceous unit and irreversible hair loss.[25] They feature some challenges: some have neither a known cause nor reliable clinicopathologic findings. There exists an inconsistent use of terminology with different terms denoting the same entities or single terms denoting different conditions.[26] Since structural changes in the course of disease usually are irreversible, there is a clear need for early intervention. With the expanding understanding of the basis of disease, there is hope for appropriate therapeutic strategies versus the currently proposed trial and error algorithms. Within the maze of varied conditions leading to scarring alopecia, the most important is to keep a neat nosologic classification in mind, based both on morphology and a pathogenic understanding. As a general rule, whatever condition targets the follicular stem cells or destroys the whole hair follicle with the extent and severity of the inflammation being determinant will result in scarring and irreversibility of hair loss.

Except for the extent and severity of disease, and possibly ethnicity, there is no single feature that justifies distinguishing AANS as a nosologic entity in its own right from DSC. We believe that AANS represents a minor form of DCS and therefore a follicular occlusion disease amenable to oral tetracyclines, oral retinoids, and intralesional corticosteroids. Since we cannot exclude a geographical bias in our and the so far published cases of AANS, it remains to be elucidated whether AANS is also observed in patients of African origin, who are known to be prone to DCS.

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Conflicts of interest

There are no conflicts of interest.