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A 5-year-old boy with a papular rash on his arm
Lichen striatus (LS) is a common benign skin condition that presents in children between the ages of 5 and 15 years.1 The rash is typically unilateral and most frequently on the extremities, although it may appear on the face, trunk, or buttocks. The lesions start as pink or skin-colored asymptomatic papules in a linear orientation following the lines of Blaschko. There may be residual postinflammatory hypo- or hyperpigmentation which often improves within a few years.
Of note, there are subsets of lichen striatus: Hypopigmented lichen striatus with minimal papules has been termed “lichen striatus albus.” Nail lichen striatus may present as onycholysis or fissuring of nails, present as an isolated finding, or more commonly in association with concurrent affected skin. Nail lichen striatus typically resolves on its own, however there are case reports of improvement with intralesional steroids.2
There is no established etiology for LS. Autoimmune disease, viruses, immunizations, medications, and hypersensitivity reactions have been associated with triggering LS in various case reports, although strength of the associations is low. Children have been reported to have LS following scarlet fever and Candida vulvitis.3 Diagnosis usually is clinical, although biopsy may be helpful for histopathologic confirmation. No work-up for associated infections or conditions is warranted.
The differential for linear papular lesions includes inflammatory linear verrucous epidermal nevus (ILVEN), blaschkitis, or linear morphea. ILVEN is a hamartoma that usually is congenital or presents in early childhood; presents with linear or whorled, hyperkeratotic papules and plaque in similar linear “line of Blaschko” patterns; and represents cutaneous mosaicism. It is often difficult to differentiate between lichen striatus and ILVEN, however lichen striatus is not congenital, and is a self-limited condition. Under dermoscopy (polarized light systems) findings of LS more frequently demonstrate gray granular pigmentation. ILVEN is more frequently associated with cerebriform pattern.4 Blaschkitis is a term for a blaschkoid inflammation of the skin that presents with more eczematous findings and histology of spongiosis, unlike the lichenoid findings of LS. It is typically accompanied by noticeable pruritus and broader bands of involved area, and has older age of onset than LS. Linear morphea is a deeper inflammatory process of the dermis or subcutaneous fat, presenting with sclerotic skin, and typically has associated atrophy.
Treatment need not be pursued for lichen striatus because it is a benign condition. The lesions typically self-resolve without any residual scarring. If patients have associated pruritus then low- to midpotency topical steroids can be used for symptomatic relief.
Dr. Kaushik is with the division of pediatric and adolescent dermatology at Rady Children’s Hospital-San Diego, and Dr. Eichenfield is chief of pediatric and adolescent dermatology at Rady Children’s Hospital-San Diego. He is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego. There are no conflicts of interest or financial disclosures for Dr. Kaushik or Dr. Eichenfield. Email them at [email protected].
References
1. Gupta D, Mathes E. Lichen Striatus. (Levy ML ed.) 2019: UpToDate.
2. Dermatol Ther. 2018 Nov;31(6):e12713.
3. Int J Dermatol. 2018 Sep;57(9):1118-9.
4. J Dermatol. 2017 Dec;44(12):e355-6.
Lichen striatus (LS) is a common benign skin condition that presents in children between the ages of 5 and 15 years.1 The rash is typically unilateral and most frequently on the extremities, although it may appear on the face, trunk, or buttocks. The lesions start as pink or skin-colored asymptomatic papules in a linear orientation following the lines of Blaschko. There may be residual postinflammatory hypo- or hyperpigmentation which often improves within a few years.
Of note, there are subsets of lichen striatus: Hypopigmented lichen striatus with minimal papules has been termed “lichen striatus albus.” Nail lichen striatus may present as onycholysis or fissuring of nails, present as an isolated finding, or more commonly in association with concurrent affected skin. Nail lichen striatus typically resolves on its own, however there are case reports of improvement with intralesional steroids.2
There is no established etiology for LS. Autoimmune disease, viruses, immunizations, medications, and hypersensitivity reactions have been associated with triggering LS in various case reports, although strength of the associations is low. Children have been reported to have LS following scarlet fever and Candida vulvitis.3 Diagnosis usually is clinical, although biopsy may be helpful for histopathologic confirmation. No work-up for associated infections or conditions is warranted.
The differential for linear papular lesions includes inflammatory linear verrucous epidermal nevus (ILVEN), blaschkitis, or linear morphea. ILVEN is a hamartoma that usually is congenital or presents in early childhood; presents with linear or whorled, hyperkeratotic papules and plaque in similar linear “line of Blaschko” patterns; and represents cutaneous mosaicism. It is often difficult to differentiate between lichen striatus and ILVEN, however lichen striatus is not congenital, and is a self-limited condition. Under dermoscopy (polarized light systems) findings of LS more frequently demonstrate gray granular pigmentation. ILVEN is more frequently associated with cerebriform pattern.4 Blaschkitis is a term for a blaschkoid inflammation of the skin that presents with more eczematous findings and histology of spongiosis, unlike the lichenoid findings of LS. It is typically accompanied by noticeable pruritus and broader bands of involved area, and has older age of onset than LS. Linear morphea is a deeper inflammatory process of the dermis or subcutaneous fat, presenting with sclerotic skin, and typically has associated atrophy.
Treatment need not be pursued for lichen striatus because it is a benign condition. The lesions typically self-resolve without any residual scarring. If patients have associated pruritus then low- to midpotency topical steroids can be used for symptomatic relief.
Dr. Kaushik is with the division of pediatric and adolescent dermatology at Rady Children’s Hospital-San Diego, and Dr. Eichenfield is chief of pediatric and adolescent dermatology at Rady Children’s Hospital-San Diego. He is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego. There are no conflicts of interest or financial disclosures for Dr. Kaushik or Dr. Eichenfield. Email them at [email protected].
References
1. Gupta D, Mathes E. Lichen Striatus. (Levy ML ed.) 2019: UpToDate.
2. Dermatol Ther. 2018 Nov;31(6):e12713.
3. Int J Dermatol. 2018 Sep;57(9):1118-9.
4. J Dermatol. 2017 Dec;44(12):e355-6.
Lichen striatus (LS) is a common benign skin condition that presents in children between the ages of 5 and 15 years.1 The rash is typically unilateral and most frequently on the extremities, although it may appear on the face, trunk, or buttocks. The lesions start as pink or skin-colored asymptomatic papules in a linear orientation following the lines of Blaschko. There may be residual postinflammatory hypo- or hyperpigmentation which often improves within a few years.
Of note, there are subsets of lichen striatus: Hypopigmented lichen striatus with minimal papules has been termed “lichen striatus albus.” Nail lichen striatus may present as onycholysis or fissuring of nails, present as an isolated finding, or more commonly in association with concurrent affected skin. Nail lichen striatus typically resolves on its own, however there are case reports of improvement with intralesional steroids.2
There is no established etiology for LS. Autoimmune disease, viruses, immunizations, medications, and hypersensitivity reactions have been associated with triggering LS in various case reports, although strength of the associations is low. Children have been reported to have LS following scarlet fever and Candida vulvitis.3 Diagnosis usually is clinical, although biopsy may be helpful for histopathologic confirmation. No work-up for associated infections or conditions is warranted.
The differential for linear papular lesions includes inflammatory linear verrucous epidermal nevus (ILVEN), blaschkitis, or linear morphea. ILVEN is a hamartoma that usually is congenital or presents in early childhood; presents with linear or whorled, hyperkeratotic papules and plaque in similar linear “line of Blaschko” patterns; and represents cutaneous mosaicism. It is often difficult to differentiate between lichen striatus and ILVEN, however lichen striatus is not congenital, and is a self-limited condition. Under dermoscopy (polarized light systems) findings of LS more frequently demonstrate gray granular pigmentation. ILVEN is more frequently associated with cerebriform pattern.4 Blaschkitis is a term for a blaschkoid inflammation of the skin that presents with more eczematous findings and histology of spongiosis, unlike the lichenoid findings of LS. It is typically accompanied by noticeable pruritus and broader bands of involved area, and has older age of onset than LS. Linear morphea is a deeper inflammatory process of the dermis or subcutaneous fat, presenting with sclerotic skin, and typically has associated atrophy.
Treatment need not be pursued for lichen striatus because it is a benign condition. The lesions typically self-resolve without any residual scarring. If patients have associated pruritus then low- to midpotency topical steroids can be used for symptomatic relief.
Dr. Kaushik is with the division of pediatric and adolescent dermatology at Rady Children’s Hospital-San Diego, and Dr. Eichenfield is chief of pediatric and adolescent dermatology at Rady Children’s Hospital-San Diego. He is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego. There are no conflicts of interest or financial disclosures for Dr. Kaushik or Dr. Eichenfield. Email them at [email protected].
References
1. Gupta D, Mathes E. Lichen Striatus. (Levy ML ed.) 2019: UpToDate.
2. Dermatol Ther. 2018 Nov;31(6):e12713.
3. Int J Dermatol. 2018 Sep;57(9):1118-9.
4. J Dermatol. 2017 Dec;44(12):e355-6.
What is your diagnosis?
Epidermal nevi are a subset of cutaneous hamartomas resulting from somatic mutations of epidermal cells, presenting as keratinocyte or epidermal appendage overgrowths. The most common type appear in a linear distribution and are termed linear epidermal nevi or linear verrucous epidermal nevi.
There are variations of epidermal nevi (EN) that can be composed of superficial epidermal keratinocytes, sebaceous glands, apocrine or eccrine glands, hair follicles, or smooth muscle. For example, many consider a nevus sebaceous to be a type of epidermal nevus as well. The incidence of EN is approximately 1 in 1,000 newborns. Postzygotic cell mutations result in a mosaic distribution that follows embryonic migration patterns, appearing in a Blaschkoid distribution.
EN present most frequently as unilateral linear or whorled hyperpigmented coalescing papules. The lesions can be present at birth or during childhood, and after appearing, grow with the patient. Typically the lesions become more raised and verrucous around puberty. The differential diagnosis of linear EN include lichen striatus, warts, and incontinentia pigmenti. Lichen striatus can be differentiated because it presents later in life and self-resolves. Verrucae are the most commonly mistaken diagnosis for EN; warts do not usually persist in the same pattern over time with proportionate growth and typically respond to locally destructive treatments such as liquid nitrogen, unlike EN. Incontinentia pigmenti presents as vesicles initially and shows a quick evolution, differentiating it from EN. Inflammatory linear verrucous epidermal nevus (ILVEN) is a variant of linear EN that has associated chronic and intermittent erythema, scale, and pruritus. Lichen nitidus often has a pruritic presentation; however, it is flat topped and skin colored, helping differentiate it from linear EN.
There has been recent research advancing gene associations for linear EN displaying many lesions associated with mosaic mutations in oncogenes. Multiple genes have been identified with EN including RAS, FGFR3, and PIK3CA1. FGFR3 and PIK3CA mutations are associated with 50% of keratinocytic nevi. Of the RAS family, the HRAS pathway has been most closely associated with nevus sebaceous. While KRAS and NRAS genes have been associated with EN, it is to a lesser degree. However, there are multiple recent case reports demonstrating a potential association of G12D mosaicism of the KRAS gene in EN with rhabdomyosarcoma and bladder cancers2.
The diagnosis of epidermal nevus syndrome should be considered when there is a nevus with associated developmental abnormality of the central nervous system, eyes, or musculoskeletal systems. The most common systemic symptoms include delays in developmental milestones, seizure disorders, coloboma, strabismus, muscle weakness, and hemihypertrophy. To date, there are six specific epidermal nevus syndromes identified: sebaceous nevus syndrome, nevus comedonicus syndrome, Becker nevus syndrome, phakomatosis pigmentokeratotica, Proteus syndrome, congenital hemidysplasia with ichthyosiform nevus and limb defects, and cutaneous-skeletal hypophosphatemia syndrome3. In addition to the syndromes described, there are reports of associations between keratinocytic nevi and ILVEN with hypophosphatemic rickets and precocious puberty.
Linear EN are rarely associated with malignant transformation to basal cell carcinoma or squamous cell carcinoma, depending on the cell type involved. Given the low risk of malignancy, the lesions do not need to be removed routinely. For small lesions, monitoring often is the preferred management. However, lesions with functional significance, or causing strangulation or deformity, can be treated with surgical excision, curettage, or laser destruction
Dr. Kaushik is with the division of pediatric and adolescent dermatology at Rady Children’s Hospital–San Diego, and Dr. Eichenfield is chief of pediatric and adolescent dermatology at Rady Children’s Hospital–San Diego. He is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego. There are no conflicts of interest or financial disclosures for Dr. Kaushik or Dr. Eichenfield. Email them at [email protected].
References
1. Pediatr Dermatol. 2004 Jul-Aug;21(4):432-9.
2. J Med Genet. 2010 Dec;47(12):859-62.
3. Pediatr Dermatol. 2018 Jan;35(1):21-9.
Epidermal nevi are a subset of cutaneous hamartomas resulting from somatic mutations of epidermal cells, presenting as keratinocyte or epidermal appendage overgrowths. The most common type appear in a linear distribution and are termed linear epidermal nevi or linear verrucous epidermal nevi.
There are variations of epidermal nevi (EN) that can be composed of superficial epidermal keratinocytes, sebaceous glands, apocrine or eccrine glands, hair follicles, or smooth muscle. For example, many consider a nevus sebaceous to be a type of epidermal nevus as well. The incidence of EN is approximately 1 in 1,000 newborns. Postzygotic cell mutations result in a mosaic distribution that follows embryonic migration patterns, appearing in a Blaschkoid distribution.
EN present most frequently as unilateral linear or whorled hyperpigmented coalescing papules. The lesions can be present at birth or during childhood, and after appearing, grow with the patient. Typically the lesions become more raised and verrucous around puberty. The differential diagnosis of linear EN include lichen striatus, warts, and incontinentia pigmenti. Lichen striatus can be differentiated because it presents later in life and self-resolves. Verrucae are the most commonly mistaken diagnosis for EN; warts do not usually persist in the same pattern over time with proportionate growth and typically respond to locally destructive treatments such as liquid nitrogen, unlike EN. Incontinentia pigmenti presents as vesicles initially and shows a quick evolution, differentiating it from EN. Inflammatory linear verrucous epidermal nevus (ILVEN) is a variant of linear EN that has associated chronic and intermittent erythema, scale, and pruritus. Lichen nitidus often has a pruritic presentation; however, it is flat topped and skin colored, helping differentiate it from linear EN.
There has been recent research advancing gene associations for linear EN displaying many lesions associated with mosaic mutations in oncogenes. Multiple genes have been identified with EN including RAS, FGFR3, and PIK3CA1. FGFR3 and PIK3CA mutations are associated with 50% of keratinocytic nevi. Of the RAS family, the HRAS pathway has been most closely associated with nevus sebaceous. While KRAS and NRAS genes have been associated with EN, it is to a lesser degree. However, there are multiple recent case reports demonstrating a potential association of G12D mosaicism of the KRAS gene in EN with rhabdomyosarcoma and bladder cancers2.
The diagnosis of epidermal nevus syndrome should be considered when there is a nevus with associated developmental abnormality of the central nervous system, eyes, or musculoskeletal systems. The most common systemic symptoms include delays in developmental milestones, seizure disorders, coloboma, strabismus, muscle weakness, and hemihypertrophy. To date, there are six specific epidermal nevus syndromes identified: sebaceous nevus syndrome, nevus comedonicus syndrome, Becker nevus syndrome, phakomatosis pigmentokeratotica, Proteus syndrome, congenital hemidysplasia with ichthyosiform nevus and limb defects, and cutaneous-skeletal hypophosphatemia syndrome3. In addition to the syndromes described, there are reports of associations between keratinocytic nevi and ILVEN with hypophosphatemic rickets and precocious puberty.
Linear EN are rarely associated with malignant transformation to basal cell carcinoma or squamous cell carcinoma, depending on the cell type involved. Given the low risk of malignancy, the lesions do not need to be removed routinely. For small lesions, monitoring often is the preferred management. However, lesions with functional significance, or causing strangulation or deformity, can be treated with surgical excision, curettage, or laser destruction
Dr. Kaushik is with the division of pediatric and adolescent dermatology at Rady Children’s Hospital–San Diego, and Dr. Eichenfield is chief of pediatric and adolescent dermatology at Rady Children’s Hospital–San Diego. He is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego. There are no conflicts of interest or financial disclosures for Dr. Kaushik or Dr. Eichenfield. Email them at [email protected].
References
1. Pediatr Dermatol. 2004 Jul-Aug;21(4):432-9.
2. J Med Genet. 2010 Dec;47(12):859-62.
3. Pediatr Dermatol. 2018 Jan;35(1):21-9.
Epidermal nevi are a subset of cutaneous hamartomas resulting from somatic mutations of epidermal cells, presenting as keratinocyte or epidermal appendage overgrowths. The most common type appear in a linear distribution and are termed linear epidermal nevi or linear verrucous epidermal nevi.
There are variations of epidermal nevi (EN) that can be composed of superficial epidermal keratinocytes, sebaceous glands, apocrine or eccrine glands, hair follicles, or smooth muscle. For example, many consider a nevus sebaceous to be a type of epidermal nevus as well. The incidence of EN is approximately 1 in 1,000 newborns. Postzygotic cell mutations result in a mosaic distribution that follows embryonic migration patterns, appearing in a Blaschkoid distribution.
EN present most frequently as unilateral linear or whorled hyperpigmented coalescing papules. The lesions can be present at birth or during childhood, and after appearing, grow with the patient. Typically the lesions become more raised and verrucous around puberty. The differential diagnosis of linear EN include lichen striatus, warts, and incontinentia pigmenti. Lichen striatus can be differentiated because it presents later in life and self-resolves. Verrucae are the most commonly mistaken diagnosis for EN; warts do not usually persist in the same pattern over time with proportionate growth and typically respond to locally destructive treatments such as liquid nitrogen, unlike EN. Incontinentia pigmenti presents as vesicles initially and shows a quick evolution, differentiating it from EN. Inflammatory linear verrucous epidermal nevus (ILVEN) is a variant of linear EN that has associated chronic and intermittent erythema, scale, and pruritus. Lichen nitidus often has a pruritic presentation; however, it is flat topped and skin colored, helping differentiate it from linear EN.
There has been recent research advancing gene associations for linear EN displaying many lesions associated with mosaic mutations in oncogenes. Multiple genes have been identified with EN including RAS, FGFR3, and PIK3CA1. FGFR3 and PIK3CA mutations are associated with 50% of keratinocytic nevi. Of the RAS family, the HRAS pathway has been most closely associated with nevus sebaceous. While KRAS and NRAS genes have been associated with EN, it is to a lesser degree. However, there are multiple recent case reports demonstrating a potential association of G12D mosaicism of the KRAS gene in EN with rhabdomyosarcoma and bladder cancers2.
The diagnosis of epidermal nevus syndrome should be considered when there is a nevus with associated developmental abnormality of the central nervous system, eyes, or musculoskeletal systems. The most common systemic symptoms include delays in developmental milestones, seizure disorders, coloboma, strabismus, muscle weakness, and hemihypertrophy. To date, there are six specific epidermal nevus syndromes identified: sebaceous nevus syndrome, nevus comedonicus syndrome, Becker nevus syndrome, phakomatosis pigmentokeratotica, Proteus syndrome, congenital hemidysplasia with ichthyosiform nevus and limb defects, and cutaneous-skeletal hypophosphatemia syndrome3. In addition to the syndromes described, there are reports of associations between keratinocytic nevi and ILVEN with hypophosphatemic rickets and precocious puberty.
Linear EN are rarely associated with malignant transformation to basal cell carcinoma or squamous cell carcinoma, depending on the cell type involved. Given the low risk of malignancy, the lesions do not need to be removed routinely. For small lesions, monitoring often is the preferred management. However, lesions with functional significance, or causing strangulation or deformity, can be treated with surgical excision, curettage, or laser destruction
Dr. Kaushik is with the division of pediatric and adolescent dermatology at Rady Children’s Hospital–San Diego, and Dr. Eichenfield is chief of pediatric and adolescent dermatology at Rady Children’s Hospital–San Diego. He is vice chair of the department of dermatology and professor of dermatology and pediatrics at the University of California, San Diego. There are no conflicts of interest or financial disclosures for Dr. Kaushik or Dr. Eichenfield. Email them at [email protected].
References
1. Pediatr Dermatol. 2004 Jul-Aug;21(4):432-9.
2. J Med Genet. 2010 Dec;47(12):859-62.
3. Pediatr Dermatol. 2018 Jan;35(1):21-9.
A 6-year-old, otherwise-healthy male is brought into clinic for evaluation of papules on his neck. The rash has been present since 1 year of age and has been growing in size proportionately. He claims there is occasional itching but no pain or redness. He does not seem to be disturbed by his rash. He has two siblings, aged 2 and 4 years, without lesions.
On physical exam, he is noted to have a linear plaque of hyperpigmented verrucous papules on his neck.