British Journal of Dermatology (1976) 95, 349.
The lines of Blaschko: a review and reconsideration OBSERVATIONS OF THE CAUSE OF CERTAIN UNUSUAL LINEAR CONDITIONS OF THE SKIN ROBERT JACKSON Division of Dermatology, Ottawa Civic Hospital, Ontario, Canada Accepted for publication 10 March 1976
SUMMARY
Blaschko's lines are the pattern assumed by many different naevoid and acquired skin diseases on the human skin and mucosae. They were described and drawn by Blaschko 75 years ago. These lines are to be distinguished from other linear patterns such as Voight's lines, Langer's lines, and the lines of innervation of the spinal nerves. They do not follow any known nervous, vascular or l5rmphatic structures in the skin. The epidermis and its appendageal structures, the melanocytes, the vascular system, and the fatty hypoderm, all, separately or in combination, may be involved in the morphological manifestations which follow Blaschko's lines. Many of the naevoid skin conditions are lifelong (e.g. linear sebaceous naevus, unilateral naevoid telangiectasia); many of the acquired skin diseases (e.g. lichen striatus, linear psoriasis) are of relatively short duration (e.g. 1-2 years). The cause of the distribution pattern is unknown. It is possibly a form of human 'mosaicism' where certain specific cells or groups of cells react differently from other cells due to chromosomal abnormalities. The embryological explanation of Blaschko's lines is not at all clear. Other markers in addition to the skin findings are needed to determine the time and the nature of the change responsible for these lines. The main purpose of this article is to introduce the concept of Blaschko's lines into the medical, paramedical, and general biological fields of science. In this way, it is hoped that some inter-reacdon can occur between those who regularly see Blaschko's lines and those who regularly see and study other chromosomal and embryological abnormalities.
'I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.' SIR ISAAC NEWTON, I 642-1727
In 1901 a most interesting book appeared (Blaschko). It was written and illustrated mainly by Blaschko, and was published as a supplement to the Proceedings of the German Dermatological Address for reprints: Suite 508, 1081 Carling Avenue, Ottawa, Ontario KiY 4G2, Canada.
349
The lines of Blaschko: a review and reconsideration OBSERVATIONS OF THE CAUSE OF CERTAIN UNUSUAL LINEAR CONDITIONS OF THE SKIN ROBERT JACKSON Division of Dermatology, Ottawa Civic Hospital, Ontario, Canada Accepted for publication 10 March 1976
SUMMARY
Blaschko's lines are the pattern assumed by many different naevoid and acquired skin diseases on the human skin and mucosae. They were described and drawn by Blaschko 75 years ago. These lines are to be distinguished from other linear patterns such as Voight's lines, Langer's lines, and the lines of innervation of the spinal nerves. They do not follow any known nervous, vascular or l5rmphatic structures in the skin. The epidermis and its appendageal structures, the melanocytes, the vascular system, and the fatty hypoderm, all, separately or in combination, may be involved in the morphological manifestations which follow Blaschko's lines. Many of the naevoid skin conditions are lifelong (e.g. linear sebaceous naevus, unilateral naevoid telangiectasia); many of the acquired skin diseases (e.g. lichen striatus, linear psoriasis) are of relatively short duration (e.g. 1-2 years). The cause of the distribution pattern is unknown. It is possibly a form of human 'mosaicism' where certain specific cells or groups of cells react differently from other cells due to chromosomal abnormalities. The embryological explanation of Blaschko's lines is not at all clear. Other markers in addition to the skin findings are needed to determine the time and the nature of the change responsible for these lines. The main purpose of this article is to introduce the concept of Blaschko's lines into the medical, paramedical, and general biological fields of science. In this way, it is hoped that some inter-reacdon can occur between those who regularly see Blaschko's lines and those who regularly see and study other chromosomal and embryological abnormalities.
'I do not know what I may appear to the world; but to myself I seem to have been only like a boy playing on the seashore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me.' SIR ISAAC NEWTON, I 642-1727
In 1901 a most interesting book appeared (Blaschko). It was written and illustrated mainly by Blaschko, and was published as a supplement to the Proceedings of the German Dermatological Address for reprints: Suite 508, 1081 Carling Avenue, Ottawa, Ontario KiY 4G2, Canada.
349
