Patient Presentation
A 9-month-old infant presented with a 1-month history of a pruritic eruption that appeared over his trunk, arms and legs, and progressed to involve his face, scalp, neck, palms and soles. Prior to presentation, the infant had been treated with oral cephalexin (Keflex) 125 mg t.i.d. for 7 days and topical hydrocortisone 1% cream without any improvement. His past medical history was unremarkable. The infant’s mother also complained of generalized pruritus. Physical examination revealed an irritable infant with multiple, widely disseminated, erythematous papules affecting the scalp, face, neck, trunk and extremities. Multiple papulovesicules and pustules with slight excoriation and impetiginization were present on the palms and soles.
What’s Your Diagnosis?
Diagnosis: SCABIES
Scabies has been known to mankind since the Middle Ages, and still affects millions of people around the world. Characterized by an intense pruritic papular eruption, superficial burrows, excoriations and secondary infection, it is caused by the highly contagious mite Sarcoptes scabiei, which is an obligate human ectoparasite. The tortoise-shaped female mite is approximately 0.3-mm long and has eight legs. The mite mates with her partner on the skin’s surface, and once fertilized, the adult female burrows into the stratum corneum. She lays two to three eggs per day and dies after 5 weeks at the end of the burrow.1 Larvae from these eggs hatch approximately 2 weeks later and emerge to the skin’s surface, where they reinfect the skin.2
Transmission occurs by skin-to-skin contact, especially in overcrowded living conditions. In adults, transmission is common during sexual contact, and infestation from fomites may also occur.3 No sex, age or racial predilection has been noted, but scabies commonly affects infants, young children, sexually active adults and the institutionalized elderly. Most patients complain of intense pruritus (particularly at night and following a hot shower), which has been associated with a hypersensitivity reaction to excreta deposited within the burrow.2
Lesions are generally symmetrically distributed and usually spare the face and neck. These include small papules and vesicles, often accompanied by plaques, pustules, or nodules.1 The pathognomonic sign of scabies is the presence of multiple burrows on the skin, typically located in the interdigital web spaces, flexural aspects of the wrist and elbows, belt line and genitals. The burrow appears as a fine, wavy, and slightly scaly line 0.2-mm to 1-cm long. A tiny mite is often visible at one end of the burrow. Although the patient may have hundreds of itching papules, often there are less than 10 burrows. Secondary lesions include papular excoriations, scaly eczematoid patches, and red-brown nodules and vesiculopustules. The burrow is often found surrounded by infiltrates of eosinophils, lymphocytes and histiocytes on histopathology.4 The diagnosis of scabies is often difficult, but a combination of pruritus (especially at night), burrows in areas of predilection, and pruritus in close family contacts are adequate for the diagnosis. The diagnosis can be confirmed microscopically by identifying mites, eggs, or scybala in the scrapings of suspicious lesions.5,6
SCABIES IN NEONATES AND INFANTS
Scabies presents differently in neonates and infants than in adults. The pathognomonic threadlike, sinuous burrows of scabies are rarely seen in neonates and infants.7 In neonates, scabies is characterized by a large number of papulovesicular and nodular lesions, eczematization, and secondary infection, often with widespread distribution of lesions on the head, neck, scalp, palms, and soles. The affected neonates may appear irritable, feed poorly and fail to thrive. The diagnosis of scabies should be entertained for any infant who has these findings.8,9 Lesions including erythematous papules, vesicles, pustules, bullae and crusts may create a “flea-bitten” appearance.9 A history of a pruritic eruption in hospital personnel or close family members is often present.8 Indiscriminate use of topical corticosteroids due to misdiagnosis of atopic dermatitis may blunt the inflammatory appearance of scabies in infants, but it does not prevent spread of the infestation.2 More importantly, it can also lead to the heavily crusted, hyperkeratotic lesions of Norwegian scabies that are usually seen only in immunocompromised patients.10 In addition, infants may experience a generalized distribution of lesions to all body areas, including the face, neck, palms and soles, which are not areas commonly affected in adults.9,11
OTHER CONDITIONS MIMICKING SCABIES IN NEONATES AND INFANTS
The differential diagnoses for scabies in neonates and infants includes infantile acropustulosis, atopic dermatitis, eosino-philic pustular folliculitis, miliaria rubra, impetigo and insect bites.
Infantile Acropustulosis. Characterized by extremely pruritic discrete and confluent vesiculopustular acral lesions appearing in crops every 2 to 4 weeks, acropustulosis of infancy is an idiopathic dermatosis that may begin any time from birth to first year of life. The 1-mm to 3-mm red papules change within a 24-hour period into papulovesicular and vesiculopustular lesions, followed by healing with scaling, post-inflammatory hyperpigmentation and sometimes signs of secondary infection. Scabies in infants can often manifest as vesiculopustular lesions on hands and feet, but the predominance of lesions on acral sites, the absence of affected contacts, and the lack of evidence of infestation by microscopic examination help to distinguish infantile acropustulosis from scabies. Moreover, many children diagnosed with infantile acropustulosis may have already been treated for scabies prior to diagnosis, with lesions persisting or recurring despite therapy.12
Atopic Dermatitis. Crusted scabies, or scabies previously treated with topical steroids, may resemble atopic dermatitis, but the presence of papulovesicular lesions in other sites, confirmation by skin scrapings, and the presence of pruritus in family members differentiate scabies from atopic dermatitis. The typical distribution of eczematous patches in atopic dermatitis is also absent in scabies. Moreover, unlike scabies, atopic dermatitis is associated with other atopic conditions including asthma, allergic rhinitis and urticaria.
Eosinophilic Pustular Folliculitis. This idiopathic dermatosis may appear from birth through first year with the majority of cases in male patients. It is characterized by crops of 1-mm to 3-mm erythematous, pruritic, crusted papules, vesicles, and pustules recurring every 2 to 4 weeks over a period of 2 to 3 years. Lesions may form annular and circinate patterns and are primarily located on the scalp and face, but may also affect the trunk and extremities. Peripheral eosinophilia and leukocytosis are commonly noted, and eosinophils without bacteria or yeast may be seen on microscopy of a pustule.8 The condition is distinguished from scabies by the absence of mites and scybala in skin scrapings and by negative history of pruritus in close contacts. Topical steroids and systemic antibiotics may result in variable improvement.
Miliaria. The relative immaturity of the eccrine ducts in the first few weeks of life may favor the closure of pores and subsequent retention of the sweat resulting in miliaria. Four types have been described: miliaria crystallina, miliaria rubra, miliaria pustulosa and miliaria profunda, of which the first two types are most commonly seen in the neonatal period. Precipitating factors include excessive warming in incubators, fevers and tight clothing or dressings. Miliaria crystallina is characterized by myriad 1-mm to 2-mm clustered monomorphous vesicles on otherwise normal looking skin. Miliaria pustulosa is typified by distinct superficial pustules in a patient having other lesions of miliaria rubra. Miliaria profunda indicates deep blockage of the pores. The lesions in all cases may be generalized, favoring skin covered by clothing and the intertriginous areas.8
Impetigo. Impetiginization of scabies may occur with a superimposed bacterial infection,2 so skin scrapings in suspicious cases should be examined to confirm antecedent scabies. Lesions of impetigo favor moist opposing surfaces and can be few or numerous, with bullae that rupture easily leaving behind red, glazed and oozing areas. Classic honey- colored crusting may be seen. Impetigo may also be associated with fever and lymphadenopathy.
Insect Bites. Insect bites appearing as grouped red pruritic papules including flea or bed bug bites may give the false impression of scabies in infants, but their pattern and distribution in exposed areas may help to differentiate them diagnostically. Skin scrapings should be examined to rule out scabies.
HOW TO TREAT AND PREVENT SCABIES
The treatment of choice for neonates, infants and young children is topical application of 5% permethrin lotion (Acticin, Elimite), which has a relatively high safety profile due to minimal absorption (2%) of the drug.13,14 Permethrin is a synthetic pyrethrin, which acts as a neurotoxin to paralyze the mites, and should be applied to the skin for 8 to 14 hours followed by re-application 1 week later. Treat the entire body surface of infants and young children, but avoid areas around the eyes and mouth.2 The lotion should be applied from the neck down in older children and adults and should include intertriginous and genital areas. A single application is associated with an overall cure rate of 89% to 92%.14 Side effects include mild transient burning, stinging and erythema. Parents should be informed that pruritus may persist for several weeks despite treatment. However, once the treatment is completed, young children may return to childcare or school.
Sulfur (5% to 10% in Petrolatum) and crotamiton 10% cream (Eurax) are alternative therapies.1 Sulfur, which is the oldest known treatment of scabies, is used in pregnant or lactating women. It should be applied nightly for 3 consecutive nights and washed off thoroughly 24 hours after the last application. Crotamiton cream is regarded less effective and is usually applied for 5 days. Lindane 1% cream was the treatment of choice before the introduction of permethrin, but due to concerns about its systemic and central nervous system toxicity (up to 10 % is absorbed), it is no longer the treatment of choice in infants and young children. Moreover, lindane-resistant cases have been reported.15 The role of oral ivermectin (Stromectol) in the treatment of scabies remains to be determined,13 but it has been reported effective in the treatment of severe crusted scabies in severely immunosuppressed patients.16 All family members and close contacts of scabies patients must be treated — even if they do not complain of pruritus. Bed linens should be washed in water at least 120°F. Dry cleaning or storage for 1 week also may be effective. Antihistamines or mild-to-intermediate strength topical corticosteroids may be used for severe pruritus. Secondarily infected scabies should be treated with topical and/or systemic antibiotics. Treatment failure is quite common and usually attributed to failure to simultaneously treat all the family members and close contacts. Patients should be warned about persistent pruritus resulting from a hypersensitive reaction, following a successful treatment of scabies. Potent topical corticosteroids or occasionally a taper dose of oral prednisone may be necessary to control the pruritus.
Patient Presentation
A 9-month-old infant presented with a 1-month history of a pruritic eruption that appeared over his trunk, arms and legs, and progressed to involve his face, scalp, neck, palms and soles. Prior to presentation, the infant had been treated with oral cephalexin (Keflex) 125 mg t.i.d. for 7 days and topical hydrocortisone 1% cream without any improvement. His past medical history was unremarkable. The infant’s mother also complained of generalized pruritus. Physical examination revealed an irritable infant with multiple, widely disseminated, erythematous papules affecting the scalp, face, neck, trunk and extremities. Multiple papulovesicules and pustules with slight excoriation and impetiginization were present on the palms and soles.
What’s Your Diagnosis?
Diagnosis: SCABIES
Scabies has been known to mankind since the Middle Ages, and still affects millions of people around the world. Characterized by an intense pruritic papular eruption, superficial burrows, excoriations and secondary infection, it is caused by the highly contagious mite Sarcoptes scabiei, which is an obligate human ectoparasite. The tortoise-shaped female mite is approximately 0.3-mm long and has eight legs. The mite mates with her partner on the skin’s surface, and once fertilized, the adult female burrows into the stratum corneum. She lays two to three eggs per day and dies after 5 weeks at the end of the burrow.1 Larvae from these eggs hatch approximately 2 weeks later and emerge to the skin’s surface, where they reinfect the skin.2
Transmission occurs by skin-to-skin contact, especially in overcrowded living conditions. In adults, transmission is common during sexual contact, and infestation from fomites may also occur.3 No sex, age or racial predilection has been noted, but scabies commonly affects infants, young children, sexually active adults and the institutionalized elderly. Most patients complain of intense pruritus (particularly at night and following a hot shower), which has been associated with a hypersensitivity reaction to excreta deposited within the burrow.2
Lesions are generally symmetrically distributed and usually spare the face and neck. These include small papules and vesicles, often accompanied by plaques, pustules, or nodules.1 The pathognomonic sign of scabies is the presence of multiple burrows on the skin, typically located in the interdigital web spaces, flexural aspects of the wrist and elbows, belt line and genitals. The burrow appears as a fine, wavy, and slightly scaly line 0.2-mm to 1-cm long. A tiny mite is often visible at one end of the burrow. Although the patient may have hundreds of itching papules, often there are less than 10 burrows. Secondary lesions include papular excoriations, scaly eczematoid patches, and red-brown nodules and vesiculopustules. The burrow is often found surrounded by infiltrates of eosinophils, lymphocytes and histiocytes on histopathology.4 The diagnosis of scabies is often difficult, but a combination of pruritus (especially at night), burrows in areas of predilection, and pruritus in close family contacts are adequate for the diagnosis. The diagnosis can be confirmed microscopically by identifying mites, eggs, or scybala in the scrapings of suspicious lesions.5,6
SCABIES IN NEONATES AND INFANTS
Scabies presents differently in neonates and infants than in adults. The pathognomonic threadlike, sinuous burrows of scabies are rarely seen in neonates and infants.7 In neonates, scabies is characterized by a large number of papulovesicular and nodular lesions, eczematization, and secondary infection, often with widespread distribution of lesions on the head, neck, scalp, palms, and soles. The affected neonates may appear irritable, feed poorly and fail to thrive. The diagnosis of scabies should be entertained for any infant who has these findings.8,9 Lesions including erythematous papules, vesicles, pustules, bullae and crusts may create a “flea-bitten” appearance.9 A history of a pruritic eruption in hospital personnel or close family members is often present.8 Indiscriminate use of topical corticosteroids due to misdiagnosis of atopic dermatitis may blunt the inflammatory appearance of scabies in infants, but it does not prevent spread of the infestation.2 More importantly, it can also lead to the heavily crusted, hyperkeratotic lesions of Norwegian scabies that are usually seen only in immunocompromised patients.10 In addition, infants may experience a generalized distribution of lesions to all body areas, including the face, neck, palms and soles, which are not areas commonly affected in adults.9,11
OTHER CONDITIONS MIMICKING SCABIES IN NEONATES AND INFANTS
The differential diagnoses for scabies in neonates and infants includes infantile acropustulosis, atopic dermatitis, eosino-philic pustular folliculitis, miliaria rubra, impetigo and insect bites.
Infantile Acropustulosis. Characterized by extremely pruritic discrete and confluent vesiculopustular acral lesions appearing in crops every 2 to 4 weeks, acropustulosis of infancy is an idiopathic dermatosis that may begin any time from birth to first year of life. The 1-mm to 3-mm red papules change within a 24-hour period into papulovesicular and vesiculopustular lesions, followed by healing with scaling, post-inflammatory hyperpigmentation and sometimes signs of secondary infection. Scabies in infants can often manifest as vesiculopustular lesions on hands and feet, but the predominance of lesions on acral sites, the absence of affected contacts, and the lack of evidence of infestation by microscopic examination help to distinguish infantile acropustulosis from scabies. Moreover, many children diagnosed with infantile acropustulosis may have already been treated for scabies prior to diagnosis, with lesions persisting or recurring despite therapy.12
Atopic Dermatitis. Crusted scabies, or scabies previously treated with topical steroids, may resemble atopic dermatitis, but the presence of papulovesicular lesions in other sites, confirmation by skin scrapings, and the presence of pruritus in family members differentiate scabies from atopic dermatitis. The typical distribution of eczematous patches in atopic dermatitis is also absent in scabies. Moreover, unlike scabies, atopic dermatitis is associated with other atopic conditions including asthma, allergic rhinitis and urticaria.
Eosinophilic Pustular Folliculitis. This idiopathic dermatosis may appear from birth through first year with the majority of cases in male patients. It is characterized by crops of 1-mm to 3-mm erythematous, pruritic, crusted papules, vesicles, and pustules recurring every 2 to 4 weeks over a period of 2 to 3 years. Lesions may form annular and circinate patterns and are primarily located on the scalp and face, but may also affect the trunk and extremities. Peripheral eosinophilia and leukocytosis are commonly noted, and eosinophils without bacteria or yeast may be seen on microscopy of a pustule.8 The condition is distinguished from scabies by the absence of mites and scybala in skin scrapings and by negative history of pruritus in close contacts. Topical steroids and systemic antibiotics may result in variable improvement.
Miliaria. The relative immaturity of the eccrine ducts in the first few weeks of life may favor the closure of pores and subsequent retention of the sweat resulting in miliaria. Four types have been described: miliaria crystallina, miliaria rubra, miliaria pustulosa and miliaria profunda, of which the first two types are most commonly seen in the neonatal period. Precipitating factors include excessive warming in incubators, fevers and tight clothing or dressings. Miliaria crystallina is characterized by myriad 1-mm to 2-mm clustered monomorphous vesicles on otherwise normal looking skin. Miliaria pustulosa is typified by distinct superficial pustules in a patient having other lesions of miliaria rubra. Miliaria profunda indicates deep blockage of the pores. The lesions in all cases may be generalized, favoring skin covered by clothing and the intertriginous areas.8
Impetigo. Impetiginization of scabies may occur with a superimposed bacterial infection,2 so skin scrapings in suspicious cases should be examined to confirm antecedent scabies. Lesions of impetigo favor moist opposing surfaces and can be few or numerous, with bullae that rupture easily leaving behind red, glazed and oozing areas. Classic honey- colored crusting may be seen. Impetigo may also be associated with fever and lymphadenopathy.
Insect Bites. Insect bites appearing as grouped red pruritic papules including flea or bed bug bites may give the false impression of scabies in infants, but their pattern and distribution in exposed areas may help to differentiate them diagnostically. Skin scrapings should be examined to rule out scabies.
HOW TO TREAT AND PREVENT SCABIES
The treatment of choice for neonates, infants and young children is topical application of 5% permethrin lotion (Acticin, Elimite), which has a relatively high safety profile due to minimal absorption (2%) of the drug.13,14 Permethrin is a synthetic pyrethrin, which acts as a neurotoxin to paralyze the mites, and should be applied to the skin for 8 to 14 hours followed by re-application 1 week later. Treat the entire body surface of infants and young children, but avoid areas around the eyes and mouth.2 The lotion should be applied from the neck down in older children and adults and should include intertriginous and genital areas. A single application is associated with an overall cure rate of 89% to 92%.14 Side effects include mild transient burning, stinging and erythema. Parents should be informed that pruritus may persist for several weeks despite treatment. However, once the treatment is completed, young children may return to childcare or school.
Sulfur (5% to 10% in Petrolatum) and crotamiton 10% cream (Eurax) are alternative therapies.1 Sulfur, which is the oldest known treatment of scabies, is used in pregnant or lactating women. It should be applied nightly for 3 consecutive nights and washed off thoroughly 24 hours after the last application. Crotamiton cream is regarded less effective and is usually applied for 5 days. Lindane 1% cream was the treatment of choice before the introduction of permethrin, but due to concerns about its systemic and central nervous system toxicity (up to 10 % is absorbed), it is no longer the treatment of choice in infants and young children. Moreover, lindane-resistant cases have been reported.15 The role of oral ivermectin (Stromectol) in the treatment of scabies remains to be determined,13 but it has been reported effective in the treatment of severe crusted scabies in severely immunosuppressed patients.16 All family members and close contacts of scabies patients must be treated — even if they do not complain of pruritus. Bed linens should be washed in water at least 120°F. Dry cleaning or storage for 1 week also may be effective. Antihistamines or mild-to-intermediate strength topical corticosteroids may be used for severe pruritus. Secondarily infected scabies should be treated with topical and/or systemic antibiotics. Treatment failure is quite common and usually attributed to failure to simultaneously treat all the family members and close contacts. Patients should be warned about persistent pruritus resulting from a hypersensitive reaction, following a successful treatment of scabies. Potent topical corticosteroids or occasionally a taper dose of oral prednisone may be necessary to control the pruritus.
Patient Presentation
A 9-month-old infant presented with a 1-month history of a pruritic eruption that appeared over his trunk, arms and legs, and progressed to involve his face, scalp, neck, palms and soles. Prior to presentation, the infant had been treated with oral cephalexin (Keflex) 125 mg t.i.d. for 7 days and topical hydrocortisone 1% cream without any improvement. His past medical history was unremarkable. The infant’s mother also complained of generalized pruritus. Physical examination revealed an irritable infant with multiple, widely disseminated, erythematous papules affecting the scalp, face, neck, trunk and extremities. Multiple papulovesicules and pustules with slight excoriation and impetiginization were present on the palms and soles.
What’s Your Diagnosis?
Diagnosis: SCABIES
Scabies has been known to mankind since the Middle Ages, and still affects millions of people around the world. Characterized by an intense pruritic papular eruption, superficial burrows, excoriations and secondary infection, it is caused by the highly contagious mite Sarcoptes scabiei, which is an obligate human ectoparasite. The tortoise-shaped female mite is approximately 0.3-mm long and has eight legs. The mite mates with her partner on the skin’s surface, and once fertilized, the adult female burrows into the stratum corneum. She lays two to three eggs per day and dies after 5 weeks at the end of the burrow.1 Larvae from these eggs hatch approximately 2 weeks later and emerge to the skin’s surface, where they reinfect the skin.2
Transmission occurs by skin-to-skin contact, especially in overcrowded living conditions. In adults, transmission is common during sexual contact, and infestation from fomites may also occur.3 No sex, age or racial predilection has been noted, but scabies commonly affects infants, young children, sexually active adults and the institutionalized elderly. Most patients complain of intense pruritus (particularly at night and following a hot shower), which has been associated with a hypersensitivity reaction to excreta deposited within the burrow.2
Lesions are generally symmetrically distributed and usually spare the face and neck. These include small papules and vesicles, often accompanied by plaques, pustules, or nodules.1 The pathognomonic sign of scabies is the presence of multiple burrows on the skin, typically located in the interdigital web spaces, flexural aspects of the wrist and elbows, belt line and genitals. The burrow appears as a fine, wavy, and slightly scaly line 0.2-mm to 1-cm long. A tiny mite is often visible at one end of the burrow. Although the patient may have hundreds of itching papules, often there are less than 10 burrows. Secondary lesions include papular excoriations, scaly eczematoid patches, and red-brown nodules and vesiculopustules. The burrow is often found surrounded by infiltrates of eosinophils, lymphocytes and histiocytes on histopathology.4 The diagnosis of scabies is often difficult, but a combination of pruritus (especially at night), burrows in areas of predilection, and pruritus in close family contacts are adequate for the diagnosis. The diagnosis can be confirmed microscopically by identifying mites, eggs, or scybala in the scrapings of suspicious lesions.5,6
SCABIES IN NEONATES AND INFANTS
Scabies presents differently in neonates and infants than in adults. The pathognomonic threadlike, sinuous burrows of scabies are rarely seen in neonates and infants.7 In neonates, scabies is characterized by a large number of papulovesicular and nodular lesions, eczematization, and secondary infection, often with widespread distribution of lesions on the head, neck, scalp, palms, and soles. The affected neonates may appear irritable, feed poorly and fail to thrive. The diagnosis of scabies should be entertained for any infant who has these findings.8,9 Lesions including erythematous papules, vesicles, pustules, bullae and crusts may create a “flea-bitten” appearance.9 A history of a pruritic eruption in hospital personnel or close family members is often present.8 Indiscriminate use of topical corticosteroids due to misdiagnosis of atopic dermatitis may blunt the inflammatory appearance of scabies in infants, but it does not prevent spread of the infestation.2 More importantly, it can also lead to the heavily crusted, hyperkeratotic lesions of Norwegian scabies that are usually seen only in immunocompromised patients.10 In addition, infants may experience a generalized distribution of lesions to all body areas, including the face, neck, palms and soles, which are not areas commonly affected in adults.9,11
OTHER CONDITIONS MIMICKING SCABIES IN NEONATES AND INFANTS
The differential diagnoses for scabies in neonates and infants includes infantile acropustulosis, atopic dermatitis, eosino-philic pustular folliculitis, miliaria rubra, impetigo and insect bites.
Infantile Acropustulosis. Characterized by extremely pruritic discrete and confluent vesiculopustular acral lesions appearing in crops every 2 to 4 weeks, acropustulosis of infancy is an idiopathic dermatosis that may begin any time from birth to first year of life. The 1-mm to 3-mm red papules change within a 24-hour period into papulovesicular and vesiculopustular lesions, followed by healing with scaling, post-inflammatory hyperpigmentation and sometimes signs of secondary infection. Scabies in infants can often manifest as vesiculopustular lesions on hands and feet, but the predominance of lesions on acral sites, the absence of affected contacts, and the lack of evidence of infestation by microscopic examination help to distinguish infantile acropustulosis from scabies. Moreover, many children diagnosed with infantile acropustulosis may have already been treated for scabies prior to diagnosis, with lesions persisting or recurring despite therapy.12
Atopic Dermatitis. Crusted scabies, or scabies previously treated with topical steroids, may resemble atopic dermatitis, but the presence of papulovesicular lesions in other sites, confirmation by skin scrapings, and the presence of pruritus in family members differentiate scabies from atopic dermatitis. The typical distribution of eczematous patches in atopic dermatitis is also absent in scabies. Moreover, unlike scabies, atopic dermatitis is associated with other atopic conditions including asthma, allergic rhinitis and urticaria.
Eosinophilic Pustular Folliculitis. This idiopathic dermatosis may appear from birth through first year with the majority of cases in male patients. It is characterized by crops of 1-mm to 3-mm erythematous, pruritic, crusted papules, vesicles, and pustules recurring every 2 to 4 weeks over a period of 2 to 3 years. Lesions may form annular and circinate patterns and are primarily located on the scalp and face, but may also affect the trunk and extremities. Peripheral eosinophilia and leukocytosis are commonly noted, and eosinophils without bacteria or yeast may be seen on microscopy of a pustule.8 The condition is distinguished from scabies by the absence of mites and scybala in skin scrapings and by negative history of pruritus in close contacts. Topical steroids and systemic antibiotics may result in variable improvement.
Miliaria. The relative immaturity of the eccrine ducts in the first few weeks of life may favor the closure of pores and subsequent retention of the sweat resulting in miliaria. Four types have been described: miliaria crystallina, miliaria rubra, miliaria pustulosa and miliaria profunda, of which the first two types are most commonly seen in the neonatal period. Precipitating factors include excessive warming in incubators, fevers and tight clothing or dressings. Miliaria crystallina is characterized by myriad 1-mm to 2-mm clustered monomorphous vesicles on otherwise normal looking skin. Miliaria pustulosa is typified by distinct superficial pustules in a patient having other lesions of miliaria rubra. Miliaria profunda indicates deep blockage of the pores. The lesions in all cases may be generalized, favoring skin covered by clothing and the intertriginous areas.8
Impetigo. Impetiginization of scabies may occur with a superimposed bacterial infection,2 so skin scrapings in suspicious cases should be examined to confirm antecedent scabies. Lesions of impetigo favor moist opposing surfaces and can be few or numerous, with bullae that rupture easily leaving behind red, glazed and oozing areas. Classic honey- colored crusting may be seen. Impetigo may also be associated with fever and lymphadenopathy.
Insect Bites. Insect bites appearing as grouped red pruritic papules including flea or bed bug bites may give the false impression of scabies in infants, but their pattern and distribution in exposed areas may help to differentiate them diagnostically. Skin scrapings should be examined to rule out scabies.
HOW TO TREAT AND PREVENT SCABIES
The treatment of choice for neonates, infants and young children is topical application of 5% permethrin lotion (Acticin, Elimite), which has a relatively high safety profile due to minimal absorption (2%) of the drug.13,14 Permethrin is a synthetic pyrethrin, which acts as a neurotoxin to paralyze the mites, and should be applied to the skin for 8 to 14 hours followed by re-application 1 week later. Treat the entire body surface of infants and young children, but avoid areas around the eyes and mouth.2 The lotion should be applied from the neck down in older children and adults and should include intertriginous and genital areas. A single application is associated with an overall cure rate of 89% to 92%.14 Side effects include mild transient burning, stinging and erythema. Parents should be informed that pruritus may persist for several weeks despite treatment. However, once the treatment is completed, young children may return to childcare or school.
Sulfur (5% to 10% in Petrolatum) and crotamiton 10% cream (Eurax) are alternative therapies.1 Sulfur, which is the oldest known treatment of scabies, is used in pregnant or lactating women. It should be applied nightly for 3 consecutive nights and washed off thoroughly 24 hours after the last application. Crotamiton cream is regarded less effective and is usually applied for 5 days. Lindane 1% cream was the treatment of choice before the introduction of permethrin, but due to concerns about its systemic and central nervous system toxicity (up to 10 % is absorbed), it is no longer the treatment of choice in infants and young children. Moreover, lindane-resistant cases have been reported.15 The role of oral ivermectin (Stromectol) in the treatment of scabies remains to be determined,13 but it has been reported effective in the treatment of severe crusted scabies in severely immunosuppressed patients.16 All family members and close contacts of scabies patients must be treated — even if they do not complain of pruritus. Bed linens should be washed in water at least 120°F. Dry cleaning or storage for 1 week also may be effective. Antihistamines or mild-to-intermediate strength topical corticosteroids may be used for severe pruritus. Secondarily infected scabies should be treated with topical and/or systemic antibiotics. Treatment failure is quite common and usually attributed to failure to simultaneously treat all the family members and close contacts. Patients should be warned about persistent pruritus resulting from a hypersensitive reaction, following a successful treatment of scabies. Potent topical corticosteroids or occasionally a taper dose of oral prednisone may be necessary to control the pruritus.
