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A 10-year-old boy has had a lesion on his left foot for almost a year. It has not responded to either topical antifungal cream (econazole, applied twice daily for weeks) or, subsequently, topical corticosteroid cream (mometazone, also applied twice daily). Frustrated by the lack of resolution, his mother brings him for evaluation.
The condition began with faint linear scaling, the area of which became gradually wider and longer. The child reports no associated symptoms, and the mother denies seeing her son manipulate, rub, or scratch the affected skin.
Aside from mild atopy—in the form of seasonal allergies and asthma—the boy is healthy.
EXAMINATION
The child is well developed, well nourished, and in no distress. He gladly permits examination of the lesion, which is located on the dorsum of the left foot, running from the lower leg to just proximal to the toes. The linear strip of skin measures 2 cm at its widest point. The lesion is tan and uniformly scaly; it exhibits no overt signs of inflammation or increased warmth or tenderness on palpation.
Examination reveals no other such lesions, or indeed any abnormalities. The adjacent toenails do not appear to be involved.
What is the diagnosis?
DISCUSSION
This child has a common condition called lichen striatus in modern times, but also known as linear lichenoid dermatitis, or (in older texts) Blaschko linear acquired inflammatory skin eruption. It has nothing to do with fungal infection.
This case illustrates a fairly typical presentation, but—as with most dermatologic conditions—there are many variants. For example, lichen striatus can present as a linear collection of scaly skin running the entire length of the leg (often beginning on the buttocks) and can even affect the toenails at its distal terminus. Although the line is usually solitary, lichen striatus can affect multiple locations simultaneously. Likewise, the lesions can run in an uninterrupted line, or stop and start at various points.
Skin type can affect the appearance of the lesions: on children with darker skin, lichen striatus usually appears lighter and on fair-skinned children, darker. The condition is more common in girls than boys (3:1) and occurs most often in those ages 5 to 15. The arms are another typical location, but it can even affect the face in rare instances. There is some support for atopy as a predisposing factor—but since almost 20% of all children are atopic, this is debatable.
Lichen striatus received its historical name because it follows Blaschko’s lines—named for Alfred Blaschko, a German dermatologist who first described the condition in 1901. These bizarre curving lines are now known to follow recognized patterns of embryonic cell migration that have nothing to do with neural, lymphatic, or vascular patterns as one might otherwise imagine. Several other skin conditions involve so-called blaschkoid features, including inflammatory linear verruciform nevi and some forms of epidermal nevi.
LS is not dangerous in any way, though it does cause considerable consternation among parents of affected children. Luckily, it causes few if any symptoms and is self-limited. A few children will complain of mild itching, for which class 4 or 5 topical steroids can be used. Within a year or two at most, the condition will resolve—albeit with occasional postinflammatory hyperpigmentation in those with darker skin.
TAKE-HOME LEARNING POINTS
- Lichen striatus is a common condition affecting children ages 5 to 15 who develop a linear, papulosquamous eruption that favors arms and leg (but can rarely involve the face).
- Not infrequently, the condition can cause dystrophy of the nails at the terminus of the lesions.
- The lesions follow Blaschko’s lines, which are thought to represent patterns of embryonic cell migration.
- The condition is seldom symptomatic, is self-limited, and rarely leaves permanent signs of damage.
A 10-year-old boy has had a lesion on his left foot for almost a year. It has not responded to either topical antifungal cream (econazole, applied twice daily for weeks) or, subsequently, topical corticosteroid cream (mometazone, also applied twice daily). Frustrated by the lack of resolution, his mother brings him for evaluation.
The condition began with faint linear scaling, the area of which became gradually wider and longer. The child reports no associated symptoms, and the mother denies seeing her son manipulate, rub, or scratch the affected skin.
Aside from mild atopy—in the form of seasonal allergies and asthma—the boy is healthy.
EXAMINATION
The child is well developed, well nourished, and in no distress. He gladly permits examination of the lesion, which is located on the dorsum of the left foot, running from the lower leg to just proximal to the toes. The linear strip of skin measures 2 cm at its widest point. The lesion is tan and uniformly scaly; it exhibits no overt signs of inflammation or increased warmth or tenderness on palpation.
Examination reveals no other such lesions, or indeed any abnormalities. The adjacent toenails do not appear to be involved.
What is the diagnosis?
DISCUSSION
This child has a common condition called lichen striatus in modern times, but also known as linear lichenoid dermatitis, or (in older texts) Blaschko linear acquired inflammatory skin eruption. It has nothing to do with fungal infection.
This case illustrates a fairly typical presentation, but—as with most dermatologic conditions—there are many variants. For example, lichen striatus can present as a linear collection of scaly skin running the entire length of the leg (often beginning on the buttocks) and can even affect the toenails at its distal terminus. Although the line is usually solitary, lichen striatus can affect multiple locations simultaneously. Likewise, the lesions can run in an uninterrupted line, or stop and start at various points.
Skin type can affect the appearance of the lesions: on children with darker skin, lichen striatus usually appears lighter and on fair-skinned children, darker. The condition is more common in girls than boys (3:1) and occurs most often in those ages 5 to 15. The arms are another typical location, but it can even affect the face in rare instances. There is some support for atopy as a predisposing factor—but since almost 20% of all children are atopic, this is debatable.
Lichen striatus received its historical name because it follows Blaschko’s lines—named for Alfred Blaschko, a German dermatologist who first described the condition in 1901. These bizarre curving lines are now known to follow recognized patterns of embryonic cell migration that have nothing to do with neural, lymphatic, or vascular patterns as one might otherwise imagine. Several other skin conditions involve so-called blaschkoid features, including inflammatory linear verruciform nevi and some forms of epidermal nevi.
LS is not dangerous in any way, though it does cause considerable consternation among parents of affected children. Luckily, it causes few if any symptoms and is self-limited. A few children will complain of mild itching, for which class 4 or 5 topical steroids can be used. Within a year or two at most, the condition will resolve—albeit with occasional postinflammatory hyperpigmentation in those with darker skin.
TAKE-HOME LEARNING POINTS
- Lichen striatus is a common condition affecting children ages 5 to 15 who develop a linear, papulosquamous eruption that favors arms and leg (but can rarely involve the face).
- Not infrequently, the condition can cause dystrophy of the nails at the terminus of the lesions.
- The lesions follow Blaschko’s lines, which are thought to represent patterns of embryonic cell migration.
- The condition is seldom symptomatic, is self-limited, and rarely leaves permanent signs of damage.
A 10-year-old boy has had a lesion on his left foot for almost a year. It has not responded to either topical antifungal cream (econazole, applied twice daily for weeks) or, subsequently, topical corticosteroid cream (mometazone, also applied twice daily). Frustrated by the lack of resolution, his mother brings him for evaluation.
The condition began with faint linear scaling, the area of which became gradually wider and longer. The child reports no associated symptoms, and the mother denies seeing her son manipulate, rub, or scratch the affected skin.
Aside from mild atopy—in the form of seasonal allergies and asthma—the boy is healthy.
EXAMINATION
The child is well developed, well nourished, and in no distress. He gladly permits examination of the lesion, which is located on the dorsum of the left foot, running from the lower leg to just proximal to the toes. The linear strip of skin measures 2 cm at its widest point. The lesion is tan and uniformly scaly; it exhibits no overt signs of inflammation or increased warmth or tenderness on palpation.
Examination reveals no other such lesions, or indeed any abnormalities. The adjacent toenails do not appear to be involved.
What is the diagnosis?
DISCUSSION
This child has a common condition called lichen striatus in modern times, but also known as linear lichenoid dermatitis, or (in older texts) Blaschko linear acquired inflammatory skin eruption. It has nothing to do with fungal infection.
This case illustrates a fairly typical presentation, but—as with most dermatologic conditions—there are many variants. For example, lichen striatus can present as a linear collection of scaly skin running the entire length of the leg (often beginning on the buttocks) and can even affect the toenails at its distal terminus. Although the line is usually solitary, lichen striatus can affect multiple locations simultaneously. Likewise, the lesions can run in an uninterrupted line, or stop and start at various points.
Skin type can affect the appearance of the lesions: on children with darker skin, lichen striatus usually appears lighter and on fair-skinned children, darker. The condition is more common in girls than boys (3:1) and occurs most often in those ages 5 to 15. The arms are another typical location, but it can even affect the face in rare instances. There is some support for atopy as a predisposing factor—but since almost 20% of all children are atopic, this is debatable.
Lichen striatus received its historical name because it follows Blaschko’s lines—named for Alfred Blaschko, a German dermatologist who first described the condition in 1901. These bizarre curving lines are now known to follow recognized patterns of embryonic cell migration that have nothing to do with neural, lymphatic, or vascular patterns as one might otherwise imagine. Several other skin conditions involve so-called blaschkoid features, including inflammatory linear verruciform nevi and some forms of epidermal nevi.
LS is not dangerous in any way, though it does cause considerable consternation among parents of affected children. Luckily, it causes few if any symptoms and is self-limited. A few children will complain of mild itching, for which class 4 or 5 topical steroids can be used. Within a year or two at most, the condition will resolve—albeit with occasional postinflammatory hyperpigmentation in those with darker skin.
TAKE-HOME LEARNING POINTS
- Lichen striatus is a common condition affecting children ages 5 to 15 who develop a linear, papulosquamous eruption that favors arms and leg (but can rarely involve the face).
- Not infrequently, the condition can cause dystrophy of the nails at the terminus of the lesions.
- The lesions follow Blaschko’s lines, which are thought to represent patterns of embryonic cell migration.
- The condition is seldom symptomatic, is self-limited, and rarely leaves permanent signs of damage.
