Lichen amyloidosus: a consequence of scratching.
BACKGROUND
Lichen amyloidosus (LA) is generally said to be a pruritic type of amyloidosis of unknown cause. Histopathologically, it is characterized by epidermal changes of lichen simplex chronicus and by deposits of amyloid in the papillary dermis that are derived from keratin peptides of necrotic keratinocytes. Chronic scratching is responsible for the development of lichen simplex chronicus and may lead to necrosis of individual keratinocytes.


OBJECTIVE
Our purpose was to evaluate whether chronic scratching may also be responsible for the formation of amyloid in LA.


METHODS
We studied patients with LA in regard to histopathologic findings, onset of pruritus, associated diseases, and response to treatment.


RESULTS
In most cases, pruritus had preceded the skin lesions. Eight of nine patients suffered from diseases other than LA that may be associated with pruritus. Histopathologically, amyloid was confined to areas that also showed signs of lichen simplex chronicus. Systemic treatment with sedating antihistamines and intense local treatment with corticosteroids were found to be effective.


CONCLUSIONS
LA is considered to be a variant of lichen simplex chronicus in which scratching leads to necrosis of keratinocytes and eventually to the formation of amyloid in the papillary dermis. Because chronic scratching seems to be the cause and not the result of the deposits of amyloid, treatment should be directed at the amelioration of pruritus.
Weyers
W
W
Center for Dermatopathology, Freiburg, Germany.
Weyers
I
I
Bonczkowitz
M
M
Diaz-Cascajo
C
C
Schill
W B
WB
D000279:Administration, Cutaneous; D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use; D000368:Aged; D000682:Amyloid / Q000378:metabolism; D000686:Amyloidosis / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D000982:Antipruritics / Q000627:therapeutic use; D002908:Chronic Disease; D003094:Collagen; D004194:Disease; D005260:Female; D006634:Histamine H1 Antagonists / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000473:pathology; D007633:Keratins / Q000378:metabolism; D007642:Keratosis / Q000473:pathology; D007868:Leg Dermatoses / Q000188:drug therapy / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009450:Neurodermatitis / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D011537:Pruritus / Q000150:complications*; D012074:Remission Induction; D012867:Skin / Q000378:metabolism / Q000473:pathology; D012871:Skin Diseases / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism / Q000473:pathology
D000305:Adrenal Cortex Hormones; D000682:Amyloid; D000982:Antipruritics; D006634:Histamine H1 Antagonists; D007633:Keratins; D003094:Collagen