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Three common rashes seen in adolescents

Rashes can occur at any age, but the three skin conditions that occur more commonly in the adolescent patient population include tinea versicolour, acanthosis nigricans and psoriasis, according to Dr. Miriam Weinstein, who gave a presentation during the Canadian Pediatric Society meeting in Toronto held this past fall.

Tinea versicolour

“Tinea versicolour is something we see more commonly in teens,” said Dr. Weinstein, a staff dermatologist at the Hospital for Sick Children in Toronto and associate professor, Faculty of Medicine, University of Toronto.

Dr. Weinstein said that sometimes younger patients are referred to her office by their general practitioner because the tinea versicolour did not clear despite a prescription for a topical antifungal.

“The reason why treatment fails is because these younger children sent to me typically do not have tinea versicolour, but rather postinflammatory hypopigmentation or pityriasis alba,” she said.

“Yes, younger patients can get tinea versicolour on occasion but it is not as common in young children as it is among adolescents.”

Acanthosis nigricans

Dr. Weinstein spoke about acanthosis nigricans, which she described as a skin condition that results in dark brown, velvety and discoloured elevated plaques on areas of the skin primarily affecting the neck, axillae and the groin.

“Acanthosis nigricans is typically seen in obese patients and in those who have type 2 diabetes, or it can be a cutaneous marker for risk of type two diabetes,” she said, adding that malignancies as a cause of acanthosis nigricans are rare among these patients and have rarely been reported in the literature.

“If I saw a slim child that did not have a family history of type two diabetes then I would do a workup to determine if there is another cause. Overall, I have exclusively seen acanthosis nigricans more so in overweight youth.

“Patients want acanthosis nigricans treated but often the best treatment involves treating the underlying conditions such as obesity or type two diabetes, and that may improve the plaques.”

Retinoids are sometimes helpful in some cases, but overall they are not that successful, Dr. Weinstein reported at the session.


Guttate psoriasis is more common in childhood than in adulthood, but starting in adolescents a clinician is more likely to see plaque psoriasis, Dr. Weinstein said.

“In guttate psoriasis, in about 50 per cent of cases there is an antecedent streptococcal infection. Guttate psoriasis has well-demarcated lesions but they are much smaller and they often have an eruptive presentation,” she added.

“It is common to have psoriasis on the hairline and it is difficult to treat scalp psoriasis mostly because it is difficult to use topical medicated products in hair-bearing areas.”

When psoriasis is in warm and moist body folds, the characteristic white and silvery scales of the disease are often not observed. Instead there will be sharply demarcated erythematous plaques, noted Dr. Weinstein.

Possible link between psoriasis, metabolic syndrome Psoriasis is now believed to be a systemic disease and one that does not just affect the skin, nails and joints. This condition is considered to be a systemic immune disorder. In addition, psoriasis has been linked to metabolic syndrome and other complications such as diabetes, and heart disease, Dr. Weinstein said.

“The association between psoriasis and the metabolic syndrome is still unclear; this is a relatively new finding that we have known about for the last decade. We are unsure about what the connections are right now,” Dr. Weinstein said.

“We do know, however, that patients who have psoriasis as defined in a particular study show a connection between abdominal obesity, impaired glucose regulation, hypertriglyceridemia, reduced levels of HDL and hypertension.”

Other evidence suggests that abdominal fat can secrete pro-inflammatory cytokines including interleukin-6 and tumour necrosis factor-alpha and these can also impact glucose metabolism. She added that other inflammatory diseases can be linked to cardiovascular disease, suggesting these connections might exist.

“Adipose cells can secrete cytokines, which could perhaps lead to a plaque of psoriasis and impaired glucose metabolism but that is one possible theory. It might actually be the plaque of psoriasis that is active and secreting cytokines that leads to adiposity and impaired glucose metabolism,” she said.

“A lot of work is being done in this area, but the question remains whether disease associations that are now well established in adult psoriasis relevant to pediatric psoriasis? The other question is, why does it matter? Well, it matters because that will have an impact on how we counsel patients about lifestyle behaviours and treatment choices.”

Treatment options available

Dr. Weinstein added that clinicians have traditionally treated plaques of psoriasis because people do not like how it looks and as a result clinicians have given patients the choice of treating or not treating.

“We explain to our patients that there are treatment options available, but if a patient isn’t bothered by the psoriasis then treatment may not be required. But now if those plaques are actually driving the systemic features of the disease then maybe we should be treating it for that reason. We do not know the answers to that yet, but it would change our treatment paradigm for sure.”

Interestingly, Dr. Weinstein explained that in Germany, researchers have looked at a subset of patients younger than the age of 20 who have psoriasis, and they found that subjects with psoriasis were twice as likely to have comorbid conditions including hypertriglyceridemia, hypertension and other inflammatory diseases. The same could hold true for the pediatric population as well.

“I ask patients or parents to speak with their primary care physicians about healthy lifestyle behaviours,” she said.

“I do, however, like to leave them with something about the importance of lifestyle change, therefore, I tend to use the 5–2–1–0 rule, which includes instructing patients to eat five fruits and vegetables daily, a maximum of two hours of screen time a day, one hour of moderate physical activity a day and zero sweetened drinks.”

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