Kirk Barber, MD, FRCPC

FigureI always find it difficult to speak with pediatricians about diaper rashes. Pediatricians look after many more children with rashes in the diaper area than I do-and all have their own secret ways to treat these children.  

The photos presented this month reveal disease entities I have seen that did not respond to conventional therapy and that became resistant "diaper rashes." You may have seen some of these "bottoms" in previous issues of 

. Next to each photograph, I have given several clues to the diagnosis. See if you can match these clues with the diagnostic choices listed below. You can check to see whether your diagnostic choices are correct on page 61.

 I hope you enjoy the diagnostic challenge.

 
 A. Granuloma gluteale infantum 
 B. Acrodermatitis enteropathica 
 C. Psoriasis with pustules (Candida) 
 D. Histiocytosis X 
 E. Atopic eczema 
 F. Lichen sclerosus et atrophicus 

Yellow-red papules, some of which are eroded and/or purpuric 

Depigmentation in a symmetric pattern about the vulva and perianal skin 

Severe "dermatitis" with erosions and pustules 

May be associated with diarrhea and failure to thrive

Initial improvement with anti-candidal therapy 

Persistence of erythema and maceration about the vulva, perianal, and flexural skin 

Often associated with a family history of psoriasis 

Multiple red-brown papules and nodules, often eroded 

Prolonged use of mid-strength potent corticosteroids in the diaper area 

Spontaneous resolution once the corticosteroids are stopped 

Erythema with scaling on convex surfaces of the thighs and suprapubic skin 

Articles

The photos presented this month reveal disease entities I have seen that did not respond to conventional therapy and that became resistant "diaper rashes." You may have seen some of these "bottoms" in previous issues of Consultant For Pediatricians. Next to each photograph, I have given several clues to the diagnosis. See if you can match these clues with the diagnostic choices listed below. You can check to see whether your diagnostic choices are correct on page 61.

Resistant "Diaper Rashes"

The mother of this school-aged girl is concerned that her child has a fungal infection in her fingernails and that the nails are destroyed forever. Your examination reveals that all 20 of her nail plates are affected similarly.

Case: Trachyonychia (Twenty-Nail Dystrophy)

--the name given to an acquired condition of the nails that often occurs as an isolated event. The more common term used currently for this condition is trachyonychia because the condition may not affect all 20 nails and similar morphological changes in the nail plate have been reported in association with alopecia areata, lichen planus, and psoriasis. The nail plate changes associated with these inflammatory conditions may precede the cutaneous findings by many months, which makes their diagnosis challenging.

I believe that there is an entity termed "twenty-nail dystrophy" that is a benign and idiopathic disorder. The nail plates have a distinct appearance and all 20 nails are dystrophic. The nail plates are lusterless and their surface appears to have been sandpapered in a longitudinal direction. The plates are thin and rough with accentuated longitudinal ridges and the cuticles appear to be "roughed up" and thickened. The free ends of the plates are brittle and rough. The nail plates do not appear to be growing. 

The major parental concerns are for the long-term future of the nails and the possibility of a fungal infection.

If the presentation is typical, I am able to reassure the parents that this is not a fungal infection of the nail plates. However, I often find it necessary to do a fungal culture to support my opinion against all of the medical and nonmedical advice that they have received to the contrary. The use of topical corticosteroids under occlusion has been advocated by some, but I have not found this approach to be successful. For that reason, and because parents tend to over-treat with topical steroids to this area, I am inclined to wait for the spontaneous resolution that almost always occurs over months to years in this childhood variant. I recommend only attention to the manicuring of the plates to avoid "catching" and the use of nail polish for cover if parents wish. 

I advise parents that I believe the condition to be idiopathic, that the nail plates will return to normal as mysteriously as they have changed, that there will not be any scarring, and that nail polish will go on smoothly for their daughter's wedding.	*

Trachyonychia in a School-Aged Girl

his 13-year-old girl comes to your office in tears. Her mother had received a note from school, advising that the nurse had found head lice and nits in her daughter's hair.

The patient's mother wants to cut off her child's hair to eliminate the lice. She is afraid to let her daughter use an insecticide to treat the head lice and asks whether there are any other options.

--is a common problem in schools today. Approximately 3% of school children are affected; this translates into millions of days lost from school every year.

The louse infests only the human head. It simultaneously sucks blood and secretes saliva, which results in an inflammatory reaction and itching. The lice cannot jump or fly, and pets are not a vector. Head-to-head contact is the mode of transmission.

The adult female louse (which lives for approximately 1 month) lays from 1 to 6 eggs per day (

). When the eggs are laid, they are translucent and attach to the hair shaft at the scalp. The eggs hatch in a week, and the nits (which are empty eggshells) remain attached to the shaft. These eggshells move with the hair as it grows at a rate of about 1 cm per month.

The basic principle I follow is not to diagnose an active head lice infestation unless I can find a living, moving louse. If I cannot find a louse on a careful initial inspection of a child's scalp, I teach the parents to "comb for detection." This involves seating the child with a dark cloth draped about his or her shoulders. A plastic or metal fine-tooth comb is then placed in the hair with the tines touching the scalp. The comb is firmly drawn down the hair from the roots to the tips. This action is repeated circumferentially around the scalp until the first louse is detected--either in the comb or on the drape. I think wet hair increases the yield, but this technique is often effective with dry hair as well.

Once the diagnosis is made, then the decision is whether to use insecticides. If the parents wish to avoid insecticides, it is possible to clear up infestations in more than one third of cases with a "wet combing" technique. The setup and actions are similar to those for the "combing for detection" technique, but the hair is first "slicked" with either a hair conditioner or oil--such as peanut or olive oil. The combing should be performed for 30 minutes once or twice daily and repeated every 3 to 4 days; the combing can stop a week after the last louse is discovered. Patients may use their regular shampoo program during this treatment period.

Insecticides offer more effective treatment; success rates exceed 90%. Permethrin, pyrethrin, and malathion are also safe if used properly. Each of these products has specific directions packaged with it. I recommend that these directions be followed exactly--particularly those that direct parents to wet the child's hair thoroughly with the product. I suggest that medication be reapplied in a week and that personal care hair items (eg, bedding, towels, hats, and clothing that the child has worn) be washed and dried at hot temperatures. I also encourage "wet combing" and the removal of nits during the first week after treatment.

Resistance to insecticides--particularly to permethrin and pyrethrin--is becoming an increasing problem (

). Advise patients not to use any insecticide treatment more than twice in a single treatment cycle. Also, a different topical insecticide should be used if reinfestation occurs within the first month after treatment.

It can be difficult to determine whether resistance is present or whether the child has been reinfested. I often ask parents to "wet comb" the child's hair: if there are many lice in various stages of development (ie, nymph to adult), then resistance is likely. And if only a few adult lice are found, then it is probable that they represent reinfestation.

Some practical points I share with parents:

•All household members should be checked at home or in the clinic, but I believe that only those who are infested need to be treated.

•I believe that a child may return to school after the first treatment--particularly if an insecticide is used.

•I advise parents that cutting or shaving their child's hair does little, if anything, to improve the success of therapy.

Oral trimethoprim/sulfamethoxazole and ivermectin have both been used successfully to treat head lice. Neither of these agents is approved for this indication, but either may be useful if all topical therapy fails.	*

A 13-year-old girl comes to your office in tears. Her mother wants to cut off her hair.

Focus on Head Lice

This skin condition is present at birth and usually has significant systemic manifestations. Would you be able to identify it in the nursery?

These color changes have been present on this child's skin since her birth. Her parents wonder whether anything can be done to "even out" the coloring.

What is this condition--and what will you tell the child's parents?

is an X-linked dominant disorder that affects the skin, bones, and nerves. The manifestations are present at birth, and the cutaneous findings are characteristic.

The lesions have 4 distinct phases that may overlap or manifest sequentially as follows:

The first (inflammatory) phase is usually present at or within 2 weeks of birth. Lesions must be differentiated from other blistering diseases of the newborn period--especially infections, such as herpes simplex. The blisters appear on an erythematous base and develop in crops over the trunk and extremities, often along the lines of Blaschko. A biopsy specimen taken during this phase will show epidermal vesicles with eosinophils as the predominant type of inflammatory cell. This phase generally resolves within the first 6 months of life.

The second (keratotic) phase is characterized by warty papules that appear in a linear pattern over the extremities. These papules may overlap with the inflammatory phase and generally resolve spontaneously within the first 2 years of life (

The third (hyperpigmented) phase is the most familiar. Linear bands of brown, blue, or gray hyperpigmentation appear in whorls and swirls that conform to the lines of Blaschko. The pigmentation usually continues to appear over the first 2 years of life: it then stabilizes and begins to fade as puberty approaches. Most children lose their pigmentation entirely. The pigmentation does not necessarily follow the exact pattern of the first 2 phases, but will follow the lines of Blaschko.

Atrophy, scarring, and hypopigmentation are the predominant clinical features during the fourth phase. Lesions can occur anywhere on the body.

Dental (75%), neurological (30%), and ophthalmological (35%) manifestations are the most commonly associated systemic issues. Children whose condition is diagnosed in the nursery should be assessed by an ophthalmologist. Retinal vascular proliferation is the most common ocular finding and may result in retinal detachment and blindness.

 a manifestation of pigmentary mosaicism. The hypopigmentation, the only cutaneous abnormality, is present at birth. The morphology is described as "splashed paint," and large surface areas are usually involved. Affected children do not typically have any associated systemic abnormalities, but there are rare reports of asso-ciated ocular and neurological abnormalities.

The pigmentary changes follow the lines of Blaschko. These lines were described in 1901 by Dr Alfred Blaschko when he presented his observations on linear dermatosis. He noted that the lines did not follow any known anatomic structures. Subsequent studies appear to prove his hypothesis that these lines have an embryonic origin.

The lines of Blaschko form a "V" over the vertebral column, an open "S" shape on the sides of the torso and lower abdomen, and an inverted "U" on the anterior arm and adjacent chest wall. They assume a linear (nondermatomal) pattern on the extremities.

There is currently no way to alter the pigmentation.	*

 Happle R. Mosaicism in human skin. Understanding the patterns and mechanisms. 

Incontinentia Pigmenti and Hypomelanosis of Ito

This 4-year-old girl was born with these cutaneous lesions. They were overlooked until recently.

What is the underlying disorder--and what clinical diagnostic test would have confirmed the diagnosis at birth?

This infant has a number of pigmented macules over her skin. 

The absolute number of lesions is important. Why?

Case 1: Tuberous sclerosis complex, confirmed by Wood light examination

The diagnostic test is a Wood light examination. An example of another child with these lesions as they appear under Wood light is shown in 

 The Wood light is ultraviolet; it exploits the fact that melanin will preferentially absorb the light and appear darker. Those areas that contain less melanin thus will be highlighted.

The diagnosis is, of course, tuberous sclerosis complex (TSC), and the skin lesions are those of "ash leaf" hypomelanotic macules. These macules are lance-ovate in shape (one end rounded and the other end a sharp point); they measure from 1 to 12 cm in diameter and may number from 1 to 50. They occur predominantly on the lower back and buttocks (

) but are found randomly distributed over the body. They were named by Dr Thomas Fitzpatrick, who thought they resembled the leaves of the eastern mountain ash tree. Nothing is absolute, however. These hypomelanotic macules come in a variety of oval shapes.

It has been shown that 5% of the general population have a single hypomelanotic macule; 1% have 2 lesions, and only 0.1% have 3. Therefore, the 1998 consensus conference on TSC has determined that 3 or more hypomelanotic macules must be present to be considered as a major diagnostic criterion of TSC.

1.Roach ES, Gomez ER, Northrup H. Tuberous sclerosis complex consensus conference: revised clinical diagnostic criteria. 

	Case 2:     The diagnosis of type 1 neurofibromatosis is based on the number of pigmented macules.

I am commonly asked to review healthy-appearing infants and children who have café-au-lait macules (CALMs) to help determine whether they have neurofibromatosis. The prototypical CALM is a well-circumscribed, evenly pigmented macule that measures from 0.2 to 4 cm at birth and that increases in size proportionate with body growth. In older children, these lesions may be quite large (25 cm or more). They occur predominantly over the lower back and buttocks in infancy. The reported incidence of CALMs in newborns is approximately 2.7%. Macules can be found in 25% to 30% of children.

What do these lesions mean? In infants, I accept 1 macule as normal and more than 3 macules as suspicious for type 1 neurofibromatosis (NF-1). If there are more than 5 macules that are 0.5 cm or larger, I recommend that the child be evaluated with the expectation that he or she does have NF-1. Multiple CALMs are present in more than 90% of children with NF-1. The presence of 6 CALMs that measure 0.5 cm or more in children and more than 1.5 cm in adolescents defines one of the major criteria necessary for the diagnosis of NF-1.

Axillary freckling (Crowe sign) is the presence of multiple 0.5- to 4-mm CALMs in the axilla. These macules appear when a child reaches 3 to 5 years of age and occur in 30% to 50 % of children with NF-1. The presence of both 6 CALMs and axillary freckling allows for the definitive diagnosis of NF-1.	*

The diagnostic test is a Wood light examination. An example of another child with these lesions as they appear under Wood light is shown in Figure B. The Wood light is ultraviolet; it exploits the fact that melanin will preferentially absorb the light and appear darker. Those areas that contain less melanin thus will be highlighted.

Tuberous Sclerosis Complex and Type 1 Neurofibromatosis 

This 6-year-old child was brought to the emergency department by her parents after these blisters suddenly appeared on her skin. She otherwise appeared to be well and was not febrile.

Your clinical examination can easily classify her condition and allow you to be very certain as to its severity. Should you worry about this child? What's the cause?

This boy presented with an inflammatory plaque on his skin that was intensely "itchy and burny." It was the third time that the lesion had occurred in the same location, and it was always associated with sore knees following gym class.

Case 1: Linear IgA dermatosis-childhood type

The development of blisters on a child's skin is one of the most worrisome events in pediatric dermatology. The diagnosis may be as simple as an insect bite reaction--or as life-threatening as toxic epidermal necrolysis.

The morphology of blisters in a child can help you quickly ascertain the seriousness of the condition. Blistering diseases are categorized by the position of the blister within the skin itself. For example, blisters associated with bullous impetigo are very flaccid or may simply be represented by an erosion because the blister cavity is through the stratum corneum, which is the most superficial aspect of the skin. In contrast, the blister cavity in bullous pemphigoid is through the basement membrane zone at the dermoepidermal junction: it produces a tense blister that is not easily brushed from the skin.

I also look for blisters on noninflamed skin. Their presence usually indicates that the condition is systemic.

This young girl presented with widespread tense blisters on inflamed and noninflamed skin (

). These lesions had a predilection for the face, lower trunk, and genitalia. A ring of blisters on the trunk (called the "string of pearls" sign) was also present. There were no lesions on this child's mucous membranes.

Her main symptoms were mild itch, discomfort, and inflammation around her genitalia. Her clinical presentation is most consistent with the diagnosis of chronic bullous dermatosis of childhood, now referred to as linear IgA dermatosis-childhood type.

The evaluation of a bullous disease of the skin invariably requires a biopsy specimen for both routine and immunofluorescence staining. Ideally, the specimen is taken from the inflammatory border of the blister and the edge of the blister cavity. Cells at these sites can define the histological nature of the process. Direct immunofluorescence further classifies the nature of the condition.

In linear IgA dermatosis-childhood type, the condition is defined by the immunofluorescence. A deposition of IgA in a linear pattern along the basement membrane zone (

) is the defining characteristic of this condition and is present in all affected persons. Routine histological evaluation (

) shows a subepidermal blister with dermal edema. Neutrophils and eosinophils invade the dermis at the blister edge.

This condition is one of early childhood: it usually occurs within the first decade. It may resolve spontaneously within a few years; virtually no patients suffer past puberty. Systemic therapy with dapsone (Avlosulfone) is the treatment of choice, and the condition is almost always quickly responsive.

A fixed drug eruption (FDE) has developed in response to the NSAID this boy had been taking to alleviate the discomfort in his knees. The most telling clinical clue is the recurrence of the lesions in the same location with each appearance.

FDE is a peculiar reaction to the ingestion of a variety of chemicals--including drugs. Although it is unusual, it is easily recognizable by its characteristics. Once you have seen one, it is easy to remember.

An FDE always occurs at the same location, although other sites may be recruited with each subsequent reaction. The reaction is usually preceded by an itch or burning at the site; this is followed by the development of an intense erythematous and edematous plaque that becomes dusky red or violaceous and which may blister. The genitalia, lips, hands, and feet are the sites of predilection. If there are multiple lesions, they will all occur at the same time; their appearance and symptoms will also be similar. The first occurrence begins within 1 to 2 weeks of the drug ingestion, but subsequent reactions usually occur within 24 hours of medication exposure. 

The lesions begin to fade over 1 to 2 weeks. The defining feature of the reaction is the dark blue-black hyperpigmentation, which occurs at all sites of reaction and which marks the sites where the lesions will recur.

The drugs most commonly associated with FDEs are trimethoprim/sulfamethoxazole, NSAIDs (ibuprofen), paracetamol (acetaminophen), antipyretics, and tetracyclines. There are lists of medications and foods known to be associated with FDE. You can confirm that a drug is implicated when a second identical reaction occurs after a repeated ingestion. 

Once you have made the diagnosis--which may occasionally require a biopsy--a detailed medication history that includes prescription and over-the-counter drugs needs to be completed. Agents that are taken intermittently are the most likely culprits. 

Unfortunately, avoidance is the only successful course of action. Once the reaction has begun, it has been my experience that nothing reverses or attenuates it.	*