Pediatric diseases in disguise

By Allison Evans, Assistant Managing Editor, October 1, 2025

Despite years of rigorous training and experience, even the best dermatologists may miss a pediatric diagnosis, particularly for dermatologists who don’t see as many pediatric patients. Some conditions simply present differently in children than adults while others may be less commonly seen in practice.

Pediatric dermatologists discuss dermatologic conditions that may be harder to diagnose in kids, as well as their common mimickers, and offer clinical clues to help improve decision-making.

Alopecia

“One hair condition that is often missed or misdiagnosed is diffuse alopecia areata, which is more of a thinning rather than what we usually think about for alopecia areata, a discrete patch or patches of hair loss that are smooth,” said Brittany Craiglow, MD, FAAD, a private practice pediatric dermatologist in Fairfield, Connecticut, and associate professor of dermatology at Yale School of Medicine.

“Alopecia areata is typically a straightforward diagnosis, but cases of mild diffuse alopecia areata can be very subtle,” Dr. Craiglow added. In more severe cases, a child may have generalized shedding at the onset, which is often initially misdiagnosed as telogen effluvium, a relatively uncommon condition in kids, she continued. “Dermatologists should examine all hair-bearing sites because patients may have patches on their extremities or involvement of eyebrows and/or eyelashes. Fingernail pitting may also provide another clue as well as a medical history of concomitant atopy.”

For Dr. Craiglow, the most helpful tool for diagnosing subtler presentations of alopecia areata in kids is trichoscopy. “In areas with thinning, you’ll often see classic signs of alopecia areata like exclamation mark hairs or yellow globules.”

A cause of hair loss that may be misdiagnosed as alopecia areata is trichotillomania or self-induced hair pulling, which can mimic traumatic alopecia, said Leah Lalor, MD, FAAD, a pediatric dermatologist at Children’s Wisconsin and associate professor at the Medical College of Wisconsin. “They look quite similar in some ways — broken hairs, scabs, and inconsistent or incomplete hair loss. Unlike adults, it may be more behavioral for kids and less stress induced,” Dr. Lalor explained.

“Alopecia areata is typically a straight-forward diagnosis, but cases of mild diffuse alopecia areata can be very subtle.”

Traumatic alopecia may also look like tinea capitis, although there are usually additional clues, she continued. “Tinea tends to be itchy, scaly, often more pustular. When trying to differentiate between these conditions, taking a thorough history is critical.”

Frequently, dermatologists can diagnose conditions visually, but in cases like this, she said, “You would need to ask questions like, ‘Did the patient have an injury to that area of the scalp?’ With a wound to the head, there can be scabbing, which can cause the hair to fall out.” The hair loss is often delayed, which can make it harder for the patient or family to connect the dots with the injury, Dr. Lalor added.

A case report published in Pediatric Dermatology discussed two young female patients with alopecia on the vertex scalp after elaborate professional hairstyling marketed as the “Princess Package” at a U.S. theme park (doi: 10.1111/pde.13487). The authors found localized alopecia followed by pain, erythema, and delayed crusting due to necrosis of the scalp.

“The hair was pulled so tightly into these updos. It’s usually the vertex scalp where the length of time and the heaviness of the hair can ‘strangulate’ the scalp in that area. They can get large wounds and then hair loss in the area,” Dr. Lalor explained.

“It’s important to ask those very specific questions — to get that social history of any recent trips to a hair salon, dance recitals, that sort of thing,” she said. “For many people with traumatic alopecia, it will grow back, although some are left with permanent scarring and the hair never grows back.”

Pediatric psoriasis

“Many of the kids that I treat for psoriasis come to me with a diagnosis of atopic dermatitis, which is much more common in kids,” Dr. Lalor said. “My understanding is frequently pediatric psoriasis can be spongiotic on a biopsy similar to atopic dermatitis, so even a biopsy is not always 100% effective at differentiating.”

“Pediatric psoriasis can differ from adult psoriasis in that there’s often facial involvement, particularly around the eyes, eyebrows, ears, and cheeks,” said Sarah Stein, MD, FAAD, director of pediatric dermatology at University of Chicago Medicine.

“Plaques on children with facial psoriasis are often not as thick, scaly, and well-defined as they classically are on the body and are often quite thin,” added Cheryl Bayart, MD, MPH, FAAD, pediatric dermatologist at Cincinnati Children’s and associate professor of pediatrics and dermatology at the University of Cincinnati.

“Like adults, a child may present with scalp involvement — or solely scalp involvement. Pediatric patients may also present with nail dystrophy before presenting with other features of the rash of psoriasis,” Dr. Stein said. The initial presentation in young people will often be guttate psoriasis, sometimes after a strep pharyngitis infection, she added.

Pediatric psoriasis can also be itchy, Dr. Lalor said. “There are just so many features that can mimic atopic dermatitis. Also, for kids, psoriasis may not be exclusively present on the classic extensor surfaces. It can occur in many different areas and may not present as characteristically as it does in adults. It’s a little less sharply defined in many children, so it can be tricky to diagnose.”

Dr. Lalor is clued into a psoriasis diagnosis by the morphology of the lesions themselves. “One of my patients had clusters of scaly, well-defined pink papules that were about a millimeter in size with little islands of normal skin in between those millimeter papules.”

Each one of those individual papules looked psoriasiform, she said. “It was just that they were clustered. It looked like a very acute lesion of psoriasis but they hadn’t connected yet to become psoriasis. You have to really think about the life of a skin disease. A 50-year-old with a 30-year history of psoriasis will look different than an eight-year-old with new psoriasis.”

Pediatric psoriasis may also be mistaken for a tinea infection, especially because the plaques are fairly well defined and can be round, Dr. Bayart said. “I have also seen a few cases where patients have been diagnosed with pigmentary disorders, like vitiligo. When psoriasis resolves, it often does leave some striking hypopigmentation.”

“Since you can’t always differentiate pediatric psoriasis and atopic dermatitis clinically, or even histologically, you may need to choose treatments that work for both, like topical steroids, narrowband UVB therapy, traditional immunosuppressants, and some JAK inhibitors,” Dr. Bayart added. “If you’re getting to the point where you’re considering prescribing biologics, it’s important to know which pathways to target.”

When differentiating between the two conditions, Dr. Lalor considers comorbid conditions as a helpful indicator. “Almost universally, there are either comorbid conditions or a strong family history of psoriasis or psoriatic arthritis. I see kids with inflammatory bowel disease who then go on to develop psoriasis with or without a history of TNF-alpha inhibitor therapy.”

Similar to adults, pediatric psoriasis patients have a higher risk of long-term health problems, including problems related to hypertension, heart disease, hyperlipidemia — conditions linked to the so-called metabolic syndrome, Dr. Stein said. “Screening for these conditions and ensuring appropriate health care maintenance with a primary care physician are important for these children.”

CTCL

The form of cutaneous T-cell lymphoma (CTCL) that children most often get is flat hypopigmented, and occasionally hyperpigmented, patches on the skin, sometimes with scales, said Dr. Bayart.

“A lot of times CTCL is diagnosed as post-inflammatory hypopigmentation secondary to something like eczema or psoriasis. Some patients are very itchy, which may further the belief that it is a type of dermatitis,” Dr. Bayart said. “It could also potentially be confused with tinea versicolor, but a clue is the morphology. Tinea versicolor is usually smaller, round-to-oval, relatively flat papules. CTCL affects larger areas as opposed to a more confetti-type look.”

This is a condition that tends to go undiagnosed for a very long time — both in adults and children. A study published in the British Journal of Dermatology reported a median delay of three years from onset to definitive diagnosis (doi: 10.1111/bjd.17258).

CTCL is so rare, many dermatologists may not ever encounter it. “When I have been concerned about CTCL, it has been in a person who I thought maybe had atopic dermatitis or a viral exanthem that was not getting better with appropriate treatments,” Dr. Lalor said.

“I had a patient that was bathing in triamcinolone, and it didn’t do anything at all for her,” Dr. Bayart noted. “That’s a red flag.”

Involvement of sun-protected areas is often quite pronounced in CTCL. If areas of the body that are protected from the sun, like the buttocks and hips, are spared, this is another indication to consider the diagnosis, according to Drs. Lalor and Bayart. “Patients who have pigmentary changes related to eczema or psoriasis are usually most pronounced in the areas that are sun exposed,” Dr. Bayart added.

Diagnosing CTCL in kids can be tricky because it tends to require a high index of suspicion and multiple biopsies, Dr. Lalor explained. Studies have found that the first biopsy is diagnostic only 20- 25% of the time (doi: 10.2340/00015555-1971). “It can be difficult to find the atypical lymphocytes, so sometimes you need to keep biopsying or do larger biopsies than is standard to diagnose other conditions to find those atypical cells.”

“Thankfully, it’s a fairly indolent condition, particularly in children,” Dr. Lalor noted. “Although it is technically a malignancy, some people consider it more of an inflammatory condition. It can be associated with other systemic problems and secondary malignancies.”

It’s important to be aware of the possibility of hemophagocytic lymphohistiocytosis (HLH), a rare, life-threating complication of CTCL that is mostly associated with cytotoxic CTCL. It may mimic a granulomatous or infectious condition, noted Dr. Bayart.

Contact dermatitis

It can be challenging to differentiate atopic dermatitis from contact dermatitis in children. “The people who most often develop contact dermatitis are patients with atopic dermatitis who have a compromised skin barrier and heightened immune response to certain things in the environment,” Dr. Bayart said.

“I suspect contact dermatitis in a patient with a long-standing history of atopic dermatitis if they have one or two really recalcitrant areas or they were very well controlled on their therapy and all of a sudden that therapy isn’t cutting it,” Dr. Bayart continued.

While some of these recalcitrant cases are patients with very severe atopic dermatitis, some may have comorbid allergic contact dermatitis, Dr. Craiglow noted. “The rates of ACD are quite high in kids with AD, especially severe AD.”

“We have to think about allergic contact dermatitis in patients who have more of an atypical presentation — like presenting a little bit older in childhood, not having classic areas affected by atopic dermatitis, or if there is heavy face and hand involvement,” Dr. Craiglow said.

Extended patch testing will also help clarify the clinical picture. “We can’t just use a T.R.U.E. Test because it may miss relevant contact allergens,” she added. “Most dermatologists don’t do extended patch testing, but if suspicion is high, it’s worthwhile to get the patient to somebody who does.”

Contact dermatitis may be misdiagnosed as an infection, Dr. Bayart said, “And we all know that people with AD are more prone to cutaneous staph infections. Clinically and histologically, contact dermatitis can look like eczema on steroids and can be very inflammatory, vesicular, and weepy. I emphasize to my residents how important it is to culture the skin if you suspect an infection.”

Atopic dermatitis has classic distributions that change over time. “In babies, it’s often the face and the extensor surfaces. In school-aged kids, it’s often the flexor surfaces, and in teenagers the hands are more severely affected. When you start to get outside of the classic distribution patterns, that can be a clue to consider contact dermatitis,” Dr. Bayart remarked.

In patients with darker skin types, atopic dermatitis may present subtly, Dr. Craiglow said. “A lot of patients may have more what we call ‘follicular eczema,’ where they have a prominence of their follicles. They’re not necessarily rashy, but they’re very itchy.”

Recalcitrant or severe eyelid dermatitis can point toward contact dermatitis. “There’s quite a few things that can trigger eyelid dermatitis, from airborne environmental allergens like pet dander and fragrances, to things on the hands that get rubbed onto the eyes like nail polish or glue from artificial nails,” Dr. Bayart explained.

RIME

“We are seeing a good bit of RIME [reactive infectious mucocutaneous eruption],” Dr. Stein said. “I don’t know whether it’s greater recognition or truly an increase in incidence. It can be seen in adults, but it’s probably more common in pediatrics, so adult dermatologists may not be as aware of it.”

At Cincinnati Children’s, Dr. Bayart sees seasonal flares likely related to viruses in the environment at a given time. “We tend to have a slew of these cases at once and then not see any for a while.”

“This very severe presentation of mucositis may be more limited to just the mucosal sites — mouth, eyes, genitalia — with very little diffuse rash. We should be looking for infectious triggers for this eruption, most commonly Mycoplasma pneumonia, although we have also seen it with influenza A and B,” she added.

Pediatricians often involve dermatologists because they may be concerned about Stevens-Johnson syndrome or impending toxic epidermal necrolysis (SJS/TEN), which can very much resemble RIME. Additionally, “part of the diagnostic criteria for both is mucositis of two separate areas — like the eyes and the mouth,” Dr. Bayart said.

SJS/TEN are most commonly drug reactions, according to Dr. Stein. “We should really be thinking about infectious triggers and broadening our evaluation for viral and bacterial causes when we see pediatric patients with a SJS-like rash with severe mucositis and targetoid skin lesions but who are not on other medications and don’t have other chronic health problems.”

RIME is typically much more mucosal predominant, Dr. Bayart said. “There can be skin findings, but they’re typically not as rapidly progressive or diffuse as you would see in SJS or TEN. Patients will often deal with mucositis for several days before they seek care. We can be a bit more assured that if this has been going on for a week, it’s probably not progressing to SJS, which evolves incredibly rapidly.”

Finding the implicated infection as the potential cause can also be helpful. Dr. Bayart recommends doing a respiratory viral panel on the patient.

“People also think about herpes simplex virus (HSV) with RIME. Especially on the oral mucosa, they can look very similar,” Dr. Bayart noted. “If you’re seeing involvement of other mucosal surfaces or having a history of a recent viral illness, it’s more likely to be RIME. Swabs for HSV PCR can be really helpful to differentiate.”

While the treatments are similar, the prognosis for RIME is much better than for SJS-TEN. “There isn’t a well-researched, controlled trial that’s proved what therapy is optimal,” Dr. Stein said. “Supportive treatments, as one would do for the spectrum of SJS/TEN, would be the first appropriate intervention.”

Patients may experience recurrences of RIME with future infections. “Physicians are familiar with recurrences in the setting of herpes simplex virus as a trigger for erythema multiforme-like eruption, and this falls into that category,” she added.

CARP

Confluent and reticulated papillomatosis (CARP), also called confluent and reticulated papillomatosis of Gougerot and Carteaud, is a rare skin condition characterized by scaly, brownish patches and papules that tend to coalesce into larger plaques primarily on the trunk, often with a net-like pattern.

“These are patients coming in reporting a long-standing rash, usually on their chest and neck. Sometimes also on their back,” said Dr. Stein. “Usually, they’ll say that it’s not symptomatic, not uncomfortable, not itchy — but bothersome in its appearance.”

“Often they’ll have been treated with treatments that we usually think of for tinea versicolor because of the similar sites of involvement. Patients may tell us they’ve been treated with anti-fungal medication but the rash didn’t improve.” Dermatologists can differentiate CARP from tinea versicolor by testing for fungus on a KOH slide.

Because the condition may occur on the neck, some physicians may diagnose it as eczema, Dr. Stein added. “It can also look velvety and dark in texture, which can mimic acanthosis nigricans in this location.”

CARP presents the same in children as adults, Dr. Stein said. “It is more commonly diagnosed in adolescence as opposed to younger children.”

“We don’t really understand what causes CARP. It will clear with appropriate treatments, but it often recurs to predisposed individuals,” she said.

Patients who tend to get CARP often have features of metabolic syndrome, Dr. Stein said. “Since there isn’t good information on the pathogenesis of CARP, we don’t know if there is a true causal link or if it’s just associative.”

“Although this condition is not dangerous or progressive,” she added, “it could be a marker to consider whether the patient needs further evaluations for their metabolic health.”

Additional DermWorld Resources