|Year : 2017 | Volume
| Issue : 1 | Page : 27-31
Lines in dermatology
Department of Dermatology, Venereology and Leprosy, Sapthagiri Institute of Medical Sciences, Bengaluru, Karnataka, India
|Date of Web Publication||28-Dec-2016|
A S Savitha
Department of Dermatology, Venereology and Leprosy, Sapthagiri Institute of Medical Sciences, Bengaluru - 560 090, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Savitha A S. Lines in dermatology. Clin Dermatol Rev 2017;1:27-31
| Introduction|| |
Various lines have been described on the skin; a few corresponding to embryonic development, muscle tension, and collagen fiber orientation; and a few imaginary to describe certain entities. Here is a compilation of named lines in dermatology.
| Antecubital Ahn's Line|| |
Antecubital Ahn's (AA) line is the linear, slightly depressed transverse skin line of the upper part of the forearm. It was assessed and reported by Ahn et al. in 1998 and named as AA lines. According to their report, the incidence of these lines is about 36.4% and significantly higher in females. Histopathologic examination showed subtle edema, separation and fragmentation of collagen bundles, and vasodilation at the transverse skin line. 
| Beau's Lines|| |
Beau's (bō) lines, first described in 1846 and named after Joseph Honoré Simon Beau, are transverse depressions in the nail plate that occur after a stressful event that causes temporary cessation of the proliferation of proximal nail matrix. They appear first at the cuticle and move distally with nail growth. Beau's lines are more apparent on the thumb and great toenails. They have a margin parallel to the lunula, when caused by a systemic disease. It is the most common and least specific nail change in a systemic disease. As the fingernail grows at the rate of 0.1 mm/day, the time course of the illness can be estimated from the position of Beau's line from proximal nail fold. The width of the furrow indicates the duration of the illness. If there is complete inhibition of nail growth for around 2 weeks, Beau's line will reach maximum depth resulting in onychomadesis. Recurrent bouts of illness may lead to the formation of series of transverse furrows/grooves. The distal limit of the furrow, if abrupt, indicates a sudden attack of disease; if sloping, a more protracted onset.  Beau's lines have been described in systemic disorders such as coronary thrombosis, measles, mumps, Kawasaki's disease, pneumonia, pulmonary embolism, and renal failure.  Idiopathic and inherited forms also occur.
| Bismuth Line|| |
Bismuth is used as an ingredient in pharmaceuticals and cosmetics. It is commonly used as a nontoxic replacement for lead in various applications. Bismuth subsalicylate is used as an antidiarrheal and formerly bismuth compounds were used to treat syphilis. Overexposure to bismuth can result in the formation of a black deposit on the gingiva known as a bismuth line. This is often the first sign of poisoning from prolonged parenteral administration of bismuth. 
| Blaschko's Lines|| |
The lines of Blaschko were described by Alfred Blaschko (1858-1922) in 1901. They represent a pattern assumed by many different nevoid and acquired skin diseases on the human skin and mucosae. These lines do not correspond to any known nervous, vascular, or lymphatic structure but represent the developmental growth pattern of the skin. The embryological basis of these lines is not clear. Several congenital conditions such as incontinentia pigmenti, Menkes syndrome, Conradi-Hunermann syndrome, Hypomelanosis of Ito, and acquired conditions such as lichen striatus [Figure 1], segmental vitiligo, linear lichen planus [Figure 2] etc. follow Blaschko's lines. The pattern of Blaschko's lines shows V-shape over the upper spine, S-shape on the abdomen, and inverted U-shape from the breast area onto the upper arm. There are perpendicular lines down the front and back of the lower extremities. As the distribution of the lines is linear, these were earlier thought to represent Koebner phenomenon, but the curvature of the lesions does not support this hypothesis. The lines of Blaschko are less well defined on the head and neck. The anatomic equivalent of Blaschko's lines has been described in the teeth and eyes as well. 
|Figure 1: The lesions of lichen striatus following Blaschko lines on upper thigh|
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|Figure 2: The lesions of linear lichen planus following Blaschko lines on upper extremity|
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| Bunny Lines|| |
Bunny lines, or nasalis rhytids, are wrinkles formed on the lateral and dorsal aspects of the nose. They typically course diagonally over the nasal side walls and bridge of nose. They occur due to the contraction of nasalis muscle. Transverse lines across the root of the nose are not related to nasalis muscle but rather due to contraction of procerus muscle seen with frowning. 
| Burton Line/Lead Line|| |
The Burton line or Burtonian line is a clinical sign found in patients with chronic lead poisoning. In lead poising, the metal gets deposited in gingiva. The bacteria act on them producing sulfides which results in pigmentation at the gingival margin. It is a very thin, black-blue line visible along the margin of the gums, at the base of the teeth. The sign was described in 1840 by Henry Burton. 
| Drug Line|| |
A distinct pattern of involvement of the upper arms in exanthematous drug eruptions was reported. Such eruptions involve the T1 dermatome with a sharp linear margin of demarcation from the spared skin served by the C5 spinal nerves. This is called drug line. Drug line corresponds to the dorsoventral pigmentary demarcation line (PDL) seen in about 20% of individuals with black skin. 
| Embryonic Milk Line|| |
The milk lines are two lines, formed by thickenings of the epidermis called mammary ridge of both genders by the 6 th week of life. They extend from axilla, down the trunk up to the groin and are precursors for mammary glands and nipples. By week nine of fetal life, most milk lines fade away, except for those in the chest area. Occasionally, milk lines will persist and present as extranumerary nipples. 
| Fingerprint Lines|| |
Fingerprint lines, also called dermatoglyphics, are ridged skin patterns on the palmar surface of hands and feet. Harold Cummins coined the term "Dermatoglyphics" in 1926. The dermatoglyphic patterns of hands and feet are formed during early fetal life between the 7 th and 21 st week of gestation. The dermatoglyphic science is based on two major facts; first, the ridges are slightly different for the fingers and no two persons, not even uniovular twins, show exactly similar fingerprint patterns, and second, the ridges are permanent throughout life and they survive superficial injuries and also environmental changes after the 21 st week of the intrauterine life. There are three major classes of fingerprints: Arches, loops, and whorls. Patterns of dermatoglyphics have been studied in various congenital disorders such as Down's syndrome, Klinefelter's syndrome and also in chronic diseases such as hypertension and diabetes mellitus. 
| Glabellar Frown Lines|| |
Glabellar lines are created by three muscles: The frontalis, the procerus, and the corrugators supercilii muscle. The corrugator supercilii and orbicularis oculi muscles move the brow medially, and the procerus and depressor supercilii pull the brow inferiorly producing vertical wrinkles on the forehead as when frowning. 
| Hart's Line|| |
The Hart's line named after David Berry Hart is the edge of the vulval vestibule. It is a clear line of demarcation between the labia minora and the epithelium of the vestibule. The vestibule is the area that lies between the labia minora and contains the openings of the urethra and vagina. 
| Horizontal Necklace Lines|| |
Some individuals, especially those with chubbier necks, have two or three horizontal "necklace" lines of skin indentation caused by the superficial musculoaponeurotic system attachments in the neck. 
| Juxtaclavicular Beaded Lines|| |
Juxtaclavicular beaded lines typical arise at puberty as an asymptomatic, linear papular eruption involving the neck and supraclavicular areas. This entity appears to be more common in African Americans than Caucasians, and a female predominance has been noted. Microscopically, the papules noted clinically appear secondary to sebaceous gland hyperplasia, which is particularly prominent in the immediate subepidermal zone. Mild papillated epidermal hyperplasia may be observed. 
| Kraissl's Lines|| |
The Kraissl's lines developed by Cornelius J Kraissl, who maintained that scars were least conspicuous when placed in wrinkle lines. Kraissl recognized that wrinkles occurred perpendicular to muscle action. From this, he developed a scheme for elective incisions which were parallel to the lines of greatest tension on the skin. They are based on research in living patients. These lines are best for elective surgery over the body as the incision heals faster with a smaller scar. 
| Langer's Lines|| |
Langer's lines, also called cleavage lines, are topological lines drawn on a map of the human body. The lines were first discovered in 1861 by Austrian anatomist Karl Langer (1819-1887). They were historically defined by the direction in which the skin of a human cadaver in rigor mortis will split when struck with a spike. Dupuytren found that the round holes had arranged themselves into elliptical incisions. They correspond to the natural orientation of collagen fibers in the dermis and are generally perpendicular to the orientation of the underlying muscle fibers. Incisions made parallel to Langer's lines may heal better and produce less scarring than those that cut across. 
| Marionette Lines|| |
Marionette lines or melomental folds/drool grooves are long vertical lines that laterally circumscribe the chin. They extend from the downturned corner of the mouth to the lateral mentum involuntarily produce a sad expression and give the appearance of advancing age. They tend to appear as the ligaments around the mouth and chin relax and begin to loosen and sag, and fatty tissues of the cheek deflate and descend during the aging process. 
| Mees' Lines|| |
Mees' lines, also known as Aldrich or Reynolds' lines, are horizontal leukonychia occurring in patients with arsenic or heavy metal poisoning, Hodgkin's lymphoma, congestive heart failure, leprosy, malaria, after chemotherapy, or carbon monoxide poisoning. Here, the nail bed is normal, but the nail itself is microscopically fragmented, due to disruption of normal growth at the nail matrix during the insult. The width of Mees' lines varies and will depend on the insult and its duration. The line will move to the nail tip with time. Mees' lines need to be distinguished from Muehrcke's lines. 
| Muehrcke's Lines|| |
Muehrcke's lines are white horizontal bands that run parallel to lunula and separated from one another and from the lunula, by stripes of pink nail. This is mainly seen in hypoalbuminemia, when the serum albumin level returns to normal and reappears if it falls again. It is possible that hypoalbuminemia produces edema of the connective tissue in front of the lunula just below the epidermis of the nail bed, changing the compact arrangement of the collagen in this area to a looser texture, resembling the structure of the lunula; hence, the whitish color. Muehrcke's lines disappear when nail is compressed. Muehrcke's lines are common in patients undergoing systemic chemotherapy. 
| Pastia's Lines|| |
Pastia lines, aka Thompson's sign are pink or red lines found in skin creases, particularly, the crease in the antecubital fossa due to capillary fragility in scarlet fever. It occurs before the appearance of the rash and persists as pigmented lines after desquamation. The sign is named after the Romanian physician Constantin Chessec Pastia (1883-1926). 
| Pigmentary Demarcation Lines|| |
PDLs, also known as Futcher's or Voight's lines, are physiological, abrupt transitions from deeper pigmented skin to lighter pigmented skin. Eight PDLs, labeled A-H, have been described.
- A - On the lateral aspect of the upper arm extending over the pectoral area
- B - On the posteromedial portion of the lower limb
- C - Mediosternal line, a vertical hypopigmented line in the pre- and para-sternal area
- D - On the posteromedial area of the spine
- E - Bilateral hypopigmented streaks, bands, or lanceolate areas over the chest in the zone between the mid-third of the clavicle and the periareolar skin
- F - "V-" shaped hyperpigmented lines between the malar prominence and the temple
- G - "W-" shaped hyperpigmented lines between the malar prominence and the temple
- H - Linear bands of hyperpigmentation from the angle of the mouth to the lateral aspects of the chin. 
| Relaxed Skin Tension Lines|| |
In 1973, Borges described the skin lines as "relaxed skin tension lines." Tension can be minimized by placing incisions parallel to relaxed skin tension lines; the incision should be placed so that closure is possible with minimal tension. Relaxed skin tension lines, also known as wrinkles, natural skin lines, lines of facial expression, or lines of minimal tension, lie perpendicular to the long axis of the underlying facial muscles, and pinching is the most reliable method of ﬁnding them. 
| Sleep Lines|| |
Sleep lines are oblique or horizontal wrinkles caused by the position in which patients sleep. Sleeping position should be considered as an etiological factor in the formation of wrinkles. These lines are sometimes single, and there are sometimes 2-3 parallel lines generally in the same area of the face, such as the lateral orbital, temporal, frontal, and buccal regions. Sleep lines are different from the lines caused by aging, as they result from a physical habit, and most people do not complain about them. Altering the sleeping position may well reduce the depth of these lines, but wrinkling with aging will continue. The lines that should be taken into consideration during operation are Langer's lines, or relaxed skin tension lines, but not sleep lines. 
| Transverse Nasal Line|| |
It is a horizontal crease across the nose where cartilage meets bone. This occurs due to differential growth of the alar and septal cartilages of the nose during childhood or as a residual embryonic groove in the frontonasal cartilage. It is often hereditary, possibly determined by an autosomal dominant gene. This is probably the same as the nasal crease associated with allergic rhinitis and thought to be caused by repeated upward rubbing of the nose: The "allergic salute."
It is obliterated spontaneously during early adult life. ,
| Wallace Line|| |
This demarcating line marks the anatomical boundary on the lateral aspect of palms and soles, where the glabrous plantar or palmar skin meets hair bearing dorsal skin. Some inflammatory problems involving palms or soles such as lichen planus, pompholyx, or the erythematous rash of Kawasaki disease display a sharp cutoff at Wallace's line. 
| Yellow Line of Pinkus|| |
A distal yellow line traversing the nail was described by Pinkus and it represents the most proximal point of attachment of the fingertip stratum corneum to the nail plate. It is also referred as onychocorneal band or junction and is the first major barrier to material passing proximally beneath the nail plate. It is possible that abnormalities of this structure may result in onycholysis, pachyonychia congenita, and pterygium inversum unguis. 
| Hinderer's Lines|| |
Hinderer's lines are used to identify the malar prominence for filler injections. One line is drawn from the lateral canthus to the commissure of the ipsilateral lip, and the other line is drawn from the nasal ala to the tragus. The fillers are placed in juxtaposition to the crossed lines in the upper outer quadrant which defines the malar prominence. 
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