cycle. In our view, the resting state of telogen doesnot, and is often mistakenly imputed to, implyshedding. A graphic example is the fur coat ofa weasel, whose follicles experience a prolongedtelogen over the winter months. Only many monthsafter the initiation of telogen, in spring, do thosefollicles receive a unique signal which initiates theshedding process. Moreover, in a recently describedmouse model to study exogen it was found thatdifferent pelage follicles in telogen shed at differenttimes.3 Moreover, the exogen process cannot simplybe a passive event for two reasons: first, the cellstructure of the telogen follicle separates the silo ofthe new anagen shaft from the silo of the restingtelogen shafts (isolating shafts of different growthphases),3 and second, prominent shedding does notoccur in the trichostatic conditions even thoughthere is extensive dynamic outward growth of theresident shafts. The signals and events of exogen aredistinctive and separate from the important stable,structure, and function of telogen.

Kurt Stenn, MDAderans Research Institute, Inc

Philadelphia, Pennsylvania

REFERENCES

1. Rebora A. Pathogenesis of androgenetic alopecia. J Am Acad

Dermatol 2004;50:777-9.

2. Stenn K, Parimoo S, Prouty S. Growth of the Hair Follicle,

a Cycling and Regenerating Biological System. In: CM Chuong,

editors. Molecular Basis of Epithelial Appendage Morphogene-

sis. Austin (TX), RG Landes Co, 1998. p. 111-30.

3. Milner Y, Sudnik J, Filippi M, Kashgarian M, Stenn KS. The

shedding phase of the hair growth cycle, exogen, is coupled to

anagen and generates a unique shaft base. J Invest Dermatol

2002;119:639-44.

doi:10.1016/j.jaad.2004.07.040

Linear lichen planus of the face and neckversus amalgam-induced ‘‘isotopic’’ cutaneouslichen planus

To the Editor: In the April 2004 issue of the Journal,Al-Mutairi et al1 reported a case of ‘‘isotopic cutane-ous lichen planus possibly related to dental amal-gam.’’ The authors assumed a causal relationshipwith an amalgam filling of a molar tooth as well aswith a preceding herpes zoster localized in the sameregion of the face and neck.

Such a relationship is hardly possible, for thefollowing reasons. The arrangement of lesions is not‘‘zosteriform’’ but follows the lines of Blaschko.2,3 InFig 1, three bands run from the submental region tothe lower lip, and in Fig 2, one band runs from the

earlobe along the mandibula to the lower lip,whereas another streak runs in a caudal direction.2

Hence, I propose to categorize this case as a typicalexample of linear lichen planus of the head and neckshowing a unilateral, systematized involvement.

For obvious reasons, this disorder cannot beinterpreted as an isotopic response to a precedingherpes zoster, nor as a sequela of an amalgam filling.

Besides, a positive reaction to patch testing withHgCl2 does not provide proof that amalgam exertedany noxious effect in this patient. If the authorswould have performed a patch test with amalgam,the reaction would have certainly been negative.4

Rudolf Happle, MDDepartment of Dermatology

Philipp UniversityMarburg, Germany

E-mail: happle@med.uni-marburg.de

REFERENCES

1. Al-Mutairi N, Sharma AK, Osama NE, Joshi A, Ayman H. Isotopic

cutaneous lichen planus possibly related to dental amalgam.

J Am Acad Dermatol 2004;50:653-4.

2. Happle R, Assim A. The lines of Blaschko on the head and neck.

J Am Acad Dermatol 2001;44:612-5.

3. Happle R. ‘‘Zosteriform’’ lichen planus: the bizarre conse-

quences of a misnomer. Acta Derm Venereol 1998;78:300.

4. Kanerva L, Rantanen T, Aalto-Korte K, Estlander T, Hannuksela

M, Harvima RJ, et al. A multicenter study of patch test reactions

with dental screening series. Am J Contact Dermat 2001;12:

83-7.

doi:10.1016/j.jaad.2004.07.039

J AM ACAD DERMATOL

VOLUME 52, NUMBER 2

Letters 375

Degos’ disease is probably a distinct entity:A review of clinical and laboratory evidence

To the Editor: I read with interest the article aboutDegos’ disease (DD) by High et al1 in the June 2004issue of the Journal and agree that (1) DD likelyinvolves vascular insult and that (2) white atrophicpapules are not actually pathognomonic for DD andcan be present in a variety of conditions, includinglupus. Histology alone, however, cannot definea disease as a non-specific entity. Clinical andlaboratory evidence suggest that systemic DD isprobably a distinct entity and, at the very least, nota collagen vascular disease.2 The eruption of lupusfrequently affects the face, and photosensitivity isa hallmark of collagen vascular disease and lupusspecifically.3 Photosensitivity is not associated withDD; moreover, its eruptions rarely, if ever, occur onthe face.2 The white atrophic papules that are oftenreferred to as pathognemonic are best described asa sensitive (rather than specific) indication of DD.

Reply

To the Editor: We are pleased to have receivedcorrespondence regarding our paper1 which de-tailed the non-specific clinical and histologicalfindings of Degos’ disease (DD) and alluded to thepossibility that this disease may represent, in manycases, a reaction pattern. It is gratifying to learn thatour paper has stimulated discussion on the matter.

Admittedly, we cannot be certain of the existenceof DD as a distinct entity. A plethora of contradictoryevidence regarding DD exists. Not only was thissummarized within our article, but it has beendetailed in the work of other investigators as citedin our paper. Ball et al2 noted also that lupus may infact represent the most common etiology for sucha clinicopathologic constellation of findings.

As Dr Scheinfeld notes, there is nothing ‘‘patho-gnomonic’’ about the clinical presentation of thecutaneous lesions ascribed to DD. While the palms,soles, face, scalp, and genitalia tend to be spared,exceptions have been noted.3-7

Dr Scheinfeld’s observation regarding photosen-sitivity is indeed a valid concern. One must consider,however, that while many forms of autoimmuneconnective tissue disease demonstrate photosensi-tivity, other forms, such as scleroderma, autoimmunevasculitis, or primary antiphospholipid antibodysyndrome, do not.8 Additionally, while discoid lupuserythematosus most commonly occurs on photo-exposed sites, it may also involve photoprotectedareas, such as the concha of the ears, the palms, andthe soles of the feet. Similarly, lupus panniculitis,with or without overlying epidermal or dermalchange, is certainly an accepted variant of lupus.Up to 70% of lupus panniculitis patients maydemonstrate a positive antinuclear antibody (ANA),and a significant number may develop systemicdisease.9 With a proclivity for the buttocks, breasts,or upper thighs, lupus panniculitis would not beconsidered photodistributed.10 While we cannotanswer directly these observed incongruities, it is

J AM ACAD DERMATOL

FEBRUARY 2005

376 Letters

In lupus, the gastrointestinal tract is affected but isnot a defining disease criteria.3 In systemic DD, thegastrointestinal tract is affected in 50% of cases andintestinal perforation is the most severe complicationand cause of death. DD can have peristomal lesionsand fistulae, neither of which are mentioned ina Medline search of these terms and lupus.2

Whereas in lupus skin biopsy specimens exam-ined by direct immunofluorescence (DIF) usuallydemonstrate positive, reproducible results, DIF inDD does not show any particular immunofluores-cence pattern. Its biopsies show wedge-shapednecrosis, a finding not commonly described in thebiopsies of lupus or other diseases. DD is invariablyfatal, usually within 2 to 3 years from the onset ofsystemic involvement. However, the range of sur-vival time from the time of diagnosis varies from lessthan 1 year to more than 12 years. Patients withcollagen vascular disease and other diseases havemore variable survival courses.

No specific laboratory test defines DD. Mostlaboratory tests are normal, with the exception ofanemia secondary to intestinal bleeding. Collagenvascular disease is strongly associated withautoantibodies, and most diseases manifest withcharacteristic laboratory abnormalities. While DDcan overlap with antiphospholipid syndrome, itusually does not. In DD, virus-like inclusions arefrequently present in endothelial cells and fi-broblasts; these are not commonly found in otherdiseases. This point is mentioned by High et al anddeserves careful note.

No successful medical therapy for systemic DDexists, which itself separates DD from other diseases.Antiplatelet drugs may reduce the number of newskin papules, but they do not abate systemic disease.Many treatments have been tried without realbenefit. Medical therapies will at least usuallyabate some of the symptoms of lupus and otherdiseases.

In sum, systemic DD is not a collagen vasculardisease, and is probably a distinct entity character-ized by: (1) an unresponsiveness to therapy; (2) thefrequent presence of cellular virus-like inclusions;(3) negative DIF findings; (4) invariable fatal courseusually in 2 to 3 years from diagnosis; (5) a lack ofphotosensitivity; and (6) a lack of facial lesions.White atrophic papules and their histology area sensitive rather than specific indication of DD.

Noah Scheinfeld, MDDepartment of Dermatology

St. Luke’s Roosevelt Hospital CenterNew York, New York

E-mail: scheinfeld@earthlink.net

REFERENCES

1. High WA, Aranda J, Patel SB, Cockerell CJ, Costner MI. Is Degos’

disease a clinical and histological end point rather than

a specific disease? J Am Acad Dermatol 2004;50:895-9.

2. Scheinfeld N. Degos’ disease. In: Emedicine Dermatology Book.

Available at: http://www.emedicine.com/derm/topic931.htm.

Accessed June 12, 2004.

3. Hildebrand J, Muller D. Systemic lupus erythematosus.

In: Emedicine Medicine Book. Available at: http://www.

emedicine.com/MED/topic2228.htm. Accessed June 12, 2004.

doi:10.1016/j.jaad.2004.06.049