NSA (neutrophilic sebaceous adenitis) secrets revealed
By Warren R. Heymann, MD, FAAD
Nov. 8, 2023
Vol. 5, No. 45
If asked what the acronym NSA means, most of us — dermatologists included — would respond, “National Security Agency.” News of security leaks (think Edward Snowden or Jack Teixeira) are in the headlines, but neutrophilic sebaceous adenitis (NSA) may be a stealth disorder to many clinicians. Learning of a novel disorder and watching it evolve in the literature over time is fascinating. NSA was first reported by Renfro et al in 1993. I remembered their case report because of its striking clinical presentation and unique histologic findings. Although I have never seen this entity in vivo (unless I have missed the diagnosis — which is always possible), its appearance in the literature is increasing and is worthy of our attention.
The index case was a healthy 18-year-old white man who presented with erythematous, indurated circinate plaques of the face with violaceous, elevated borders. The lesions began one month after a 1-week course of cephalexin administered for bronchitis. No mucocutaneous or systemic findings were noted. Treatment with clotrimazole and betamethasone dipropionate cream over 3 weeks led to partial clearing; however, the process recurred several times in the next few months. Empiric treatment with tetracycline and griseofulvin was ineffective. Systemic steroid therapy cleared the eruption, with complete resolution at 10 months. His work-up included a normal CBC, chemistry profile, ESR, ANA, RPR, urinalysis, and KOH examination and culture. Histologic examination of a biopsy specimen demonstrated a superficial and deep perivascular and perifollicular mononuclear infiltrate; several sebaceous lobules were distended with scattered necrotic sebocytes accompanied by collections of neutrophils admixed with a few lymphocytes. The PAS stain was negative for hyphae, as were stains for other organisms. The authors compared NSA to a similar, presumably autoimmune disorder in dogs called sebaceous adenitis, acknowledging that the etiology for both diseases was unknown. (1)
Martins et al reported a similar case in a 32-year-old man with arcuate, infiltrated facial plaques, which cleared spontaneously within a month without therapy. Histologically, the picture was similar, although neutrophils were rare. The authors considered that this might be the case in older lesions; they suggested that a more appropriate term for this disorder should be sebaceous adenitis. (Spoiler alert — NSA remains the name of this dermatosis.) (2)
The third report was a 34-year-old man with recurrent lesions of his forehead, cheeks, and upper chest, appearing in 4 consecutive summers lasting 1 to 2 months. Porphyrin and autoimmune studies, including direct immunofluorescence, were negative. The biopsy demonstrated NSA. He was treated with photoprotection, topical steroids, and hydroxychloroquine. The authors were the first to suggest that NSA could be a photodermatosis. (3)
Ram-Wolff et al reported the first case of NSA in a woman. A 25-year-old woman presented with recurrent lesions on her face, upper chest, and arms with erythematous, indurated circinate plaques associated with some pustules after “sunny holidays.” As opposed to prior reports, she had a low-grade fever and lymphadenopathy. Her biopsy showed features of NSA. Topical steroids and photoprotection led to regression of the lesions. The authors questioned whether this was a photodermatosis or triggered by heat because some lesions were not on exposed sites. (4) Cunningham et al reported biopsy-proven NSA on the face and back in a 20+ year-old-man whose lesions appeared when visiting Miami, Florida. This was accompanied by a febrile illness with joint pain and lymphadenopathy, which resolved without treatment. His cutaneous lesions resolved with a 3-week prednisone taper. (5) Another case of biopsy-proven, sunlight-induced NSA manifesting as “juicy” annular/targetoid lesions of the face and chest of a 38-year-old man was reported by Chikeka et al. (6)
Therapeutically, treatments for NSA have run the gamut from steroids (topical and systemic), antibiotics (topical and systemic), isotretinoin, and dapsone. (5,7) Calcineurin inhibitors, JAK inhibitors, and PDE-4 inhibitors have not yet been reported for NSA.
Other variants of NS include: 1) vulval sebaceous adenitis presenting as painful, yellowish-orange papules/nodules recurring at the vulval mucocutaneous junction or mucosa during the luteal phase of the menstrual cycle (8); and 2) NSA associated with Demodex brevis presenting as an annular lesion on the nasal bridge of a 61-year-old man. (9)
Despite the increasing number of reports of NSA, there are too few to make profound generalizations. Astute dermatologists should consider the diagnosis if there are indurated arciform lesions on the face and upper torso, where the differential diagnosis includes lupus, granuloma annulare, tinea, or a gyrate erythema. Many cases appear to be photo-induced, and most are asymptomatic, although occasionally accompanied by systemic symptoms (low-grade fever, lymphadenopathy). The prognosis is excellent and therapeutic options abound (although most clinicians would likely commence with topical steroids).
Thirty years ago, Renfro et al concluded their report stating, “Further study is warranted if other patients with this reaction pattern are identified.” (1) For this NSA, the more of its secrets revealed, the better.
Point to Remember: Neutrophilic sebaceous adenitis (NSA) usually manifests as arciform lesions of the face and upper trunk, most frequently in younger men, and often photo-induced. Occasionally there are systemic symptoms. Further research is warranted to understand this possibly underrecognized disorder.
Our expert’s viewpoint
Mark Jacobson, MD
As noted by Dr. Heymann in his excellent synopsis of neutrophilic sebaceous adenitis (NSA) which we described 30 years ago, the entity remains rare with only sporadic case reports. It is so rare that to this day I can only recall rendering the diagnosis twice subsequently. Both of these cases were confirmed clinically and had a similar appearance and were presented as a poster at the annual meeting of the American Academy of Dermatology in 2007. (10) Given the striking arcuate plaques distributed in areas exposed to sunlight, the most likely pathophysiology remains as we hypothesized, to wit: concentration of a photosensitizing antigen (topically applied, ingested, or inhaled) in sebaceous glands. The outlier would appear to be the cases reported by Tohyama et al of genital lesions. (8) Given the vastly different clinical presentations, these are most likely a different entity modulated through hormonal alterations but with a similar histopathological pathway. The same would apply to the original cases reported in the veterinary literature where sebaceous adenitis was first described. (11)
Renfro L, Kopf AW, Gutterman A, Gottlieb GJ, Jacobson M. Neutrophilic sebaceous adenitis. Arch Dermatol. 1993 Jul;129(7):910-1. doi: 10.1001/archderm.1993.01680280100027. PMID: 8323320.
Martins C, Tellechea O, Mariano A, Baptista AP. Sebaceous adenitis. J Am Acad Dermatol. 1997 May;36(5 Pt 2):845-6. doi: 10.1016/s0190-9622(97)70037-9. PMID: 9146564.
Sanz Trelles A, Gómez Moyano E. A new case of neutrophilic sebaceous adenitis: A photodermatosis? J Am Acad Dermatol. 2009 May;60(5):887-8. doi: 10.1016/j.jaad.2008.11.004. PMID: 19389541.
Ram-Wolff C, Halabi-Tawil M, Vignon-Pennamen MD, Bagot M, Petit A. Adénite sébacée neutrophilique chez une femme [Neutrophilic sebaceous adenitis in a woman]. Ann Dermatol Venereol. 2013 Nov;140(11):708-12. French. doi: 10.1016/j.annder.2013.07.004. Epub 2013 Aug 6. PMID: 24206807.
Cunningham M, Rogers R, Greene L. Annular plaques with raised erythematous-violaceous borders on the face and torso. JAMA Dermatol. 2014 Nov;150(11):1225-6. doi: 10.1001/jamadermatol.2014.2103. PMID: 25271813.
Chikeka I, Kazlouskaya M, Kazlouskaya V. An unusual rash provoked by light. Int J Dermatol. 2023 May;62(5):e304-e305. doi: 10.1111/ijd.16149. Epub 2022 Mar 4. PMID: 35244937.
Yoshizaki A, Fujii K, Kanekura T. Neutrophilic sebaceous adenitis treated successfully with diaminodiphenyl sulfone. J Dermatol. 2023 Jan 26. doi: 10.1111/1346-8138.16735. Epub ahead of print. PMID: 36700519.
Tohyama M, Matsumoto K, Sayama K. Two cases of genital neutrophilic sebaceous adenitis. J Dermatol. 2016 Oct;43(10):1221-1223. doi: 10.1111/1346-8138.13448. PMID: 27178726.
Liaqat M, Wilson LH, Wada D, Florell SR, Bowen AR. Neutrophilic sebaceous adenitis with intralobular Demodex mites: a case report and review of the literature. Am J Dermatopathol. 2015 Apr;37(4):315-8. doi: 10.1097/DAD.0000000000000099. PMID: 25229566.
Newman, J,; Sicari, M, Hayman, R, Jacobson, M. Neutrophilic sebaceous adenitis: A report of 2 cases. J,Am Acad. Dermatol. 56(2), Suppl 2 AB56 Feb. 2007 doi:10.1016/j.jaad.2006.10.2
Scott DW. Granulomatous sebaceous adenitis in dogs. J Am Anim Hosp Assoc. 1986;22:631–634.
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