Correspondetice 393

Figure 2. Hair knot with entire cuticle slightly flat-tened. (Magnification 300x.)

hyperhidrosis of the scalp. Hair growth is usuallyabnormal—short and twisted, with longitudinal fis-suring and fracturing, and only one knot locatednear the free end of the hair. There is no similar con-dition in the patient's family. No systemic abnor-malities are revealed by physical examination, al-though Pratt reported a patient who was partiallydeaf and had a cleft palate (1). The cause of knotformation is unknown. Savill et al suggested thatshort curly hair of relatively flat shape was most of-ten affected (4). These flat hairs do not lie flat on alevel surface but recoil into spirals. This recoilingmay lead to entanglement, which by chance pro-duces a knot, resulting in trichonodosis (4). We be-lieve that knot formation is related to the flattenedsections present at irregular intervals along the hairshaft. The longitudinal flssuring of the shaft and itsincreased fragility may lead to alopecia and inabilityof the hair to grow long.

REFERENCES

1. Pratt AG. Trichonodosis. Arch Dermatol Syph 1947;56:267-268.

2. Weiner MA. Trichonodosis. Arch Dermatol Syph

3. Scott MJ. Trichonodosis. Arch Dermatol Syph 1951;63:769-771.

4. English DT, Jones HE. Trichonodosis. Arch Derma-tol 1973; 107:77-79.

WEN-YUAN ZHU, M.D.MING-YU XIA, M.D.Nanjing. People's Republic of China

BULLOUS LICHEN PLANUS

To the Editor:A 4-year-old girl had variably sized, violaceous,

mactjlar lesions arranged in an annular configura-tion on the trunk (Fig. 1). Her parents reported aone-month history of vesiculobullous lesions thatappeared over apparently normal skin of the face,trunk, and limbs, also in an annular pattem. Theselesions ruptured and healed without treatment overthree to four weeks, leaving behind violaceous mac-ules. A provisional diagnosis of bullous lichen pla-nus was considered. The child had no history of anylesions suggestive of classic lichen planus or of mu-cosal lesions. No history of any drug intake prior tothese lesions was obtained.

Routine laboratory investigations revealed an es-sentially normal hemogram, urine, and stool exam-ination. A skin biopsy specimen from the niacularlesion revealed hyperkeratosis, irregular acantho-sis, and focal hypergranulosis with a thick bandlikedermal infiltrate composed of lymphonionotiuclearcells in close approximation to the epidermis. There

Figure 1. Large violaceous macules in an annular pat-tern on the trunk.

394 Pediatric Dermatology Vol. 10 No. 4 December 1993

was also basal cell degeneration. Direct immunoflu-orescence study of the skin was negative for IgM.The diagnosis of lichen planus was thus confirmed.

Lichen planus is tincommon in children (1-3) andbiiUous lichen planus is even more rare (4—6). Bul-lous lichen planus classically follows an attack ofgeneralized lichen planus. The lesions are usuallylocalized to the extremities. They may very rarelyarise from normal skin, prexisting papules, or ery-thematous patches (7).

This rare variatit of lichen planus may at times beconfused with other bullous dermatoses such asbullous impetigo, bullous pemphigoid, or lichen pla-nus pemphigoides unless associated with classic li-chen planus lesions elsewhere on the body (1,2,7).

Our patient, it would seem, developed lesions ofbullous lichen planus de novo in an annular pattern,which, to the best of our knowledge, has not beenreported in the literature. An annular pattern of le-sions with classic papular lesions of lichen planus isnot uncommon and occurs in up to 10% of patientswith lichen planus. The pattern is scattered amonglesions of typical lichen planus and is most fre-quently present on the glans penis (1).

REFERENCES

1. Arndt KA. Lichen planus. In: Fitzpatrick TB, EisenAZ, Wolff K, Freedberg IM, Austen KF. eds. Der-matology in general medicine. New York: McGraw-Hill, 1987:967-973.

2. Black MM. Lichen planus and lichenoid disorders.In: Champion RH, Burton JL, Ebling FJG, eds. Text-book of dermatology. Oxford: Blackwell, 1992:1675-1698.

3. Kanwar AJ, Handa S, Ghosh S, Kaur S. Lichen pla-nus in childhood: a report of 17 patients. Pediatr Der-matol 199I;8(4):288-291.

4. Altman J. Perry HO. The variations and course of ii-chen planus. Arch Dermatol 1961;84:179-191.

5. Singh OP, Kanwar AJ. Lichen planus in India: an ap-praisal of 441 cases. Int J Dermato! 1976; 15:752-756.

6. Sarkany 1, Carron GA, Jones HH. Lichen pJanuspemphigoides. Trans Rep St. Johns Hosp DermatolSoc London 1964;50:50-55.

7. Kwee DJ, Dufresne RG, Ellis DL. Childhood bullouslichen planus. Pediatr Dermatol 1987;4(4):325-327.

SANJEEV HANDA, M.D.AMRINDER J. KANWAR. M.D.Chandigarh, India