Pediatric Dermatology

Update on Pediatric Psoriasis

Cutis. 2015 March;95(3):147-152

Pediatric psoriasis accounts for approximately one-third of all cases of psoriasis. Although pediatric psoriasis was always understood to be a chronic inflammatory dermatosis, recent data suggest that pediatric psoriasis, similar to its adult equivalent, is part of a generalized inflammatory diathesis associated with metabolic syndrome, including obesity/overweight status, hypertriglyceridemia, high blood pressure, and insulin resistance. Given the recent proliferation of data demonstrating the generalized inflammatory nature of psoriasis, a new emphasis on adopting a healthier lifestyle and weight control as well as systemic therapies has emerged in the literature. This article briefly reviews selected studies published in the last 2 years that are pertinent to pediatric psoriasis.

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Practice Points

The majority of children with psoriasis have severe disease, scalp involvement, and a family history.
Pediatric psoriasis is associated with metabolic syndrome, especially obesity.
Anxiety and depression may be noted in children with psoriasis as well as their caregivers.

References

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3. Silverberg NB. Update on pediatric psoriasis, part 2: therapeutic management. Cutis. 2010;86:172-176.

4. Cather JC. Psoriasis in children and women: addressing some special needs. Semin Cutan Med Surg. 2014;33(2 suppl 2):S42-S44.

5. Khorsand K, Sidbury R. Recent advances in pediatric dermatology. Arch Dis Child. 2014;99:944-948.

6. Mercy K, Kwasny M, Cordoro KM, et al. Clinical manifestations of pediatric psoriasis: results of a multicenter study in the United States. Pediatr Dermatol. 2013;30:424-428.

7. Gudjonsson JE, Thorarinsson AM, Sigurgeirsson B, et al. Streptococcal throat infections and exacerbation of chronic plaque psoriasis: a prospective study. Br J Dermatol. 2003;149:530-534.

8. Ferran M, Galván AB, Rincón C, et al. Streptococcus induces circulating CLA(+) memory T-cell-dependent epidermal cell activation in psoriasis. J Invest Dermatol. 2013;133:999-1007.

9. Gul Mert G, Incecik F, Gunasti S, et al. Psoriasiform drug eruption associated with sodium valproate [published online ahead of print November 13, 2013]. Case Rep Pediatr. 2013;2013:823469.

10. Chang MW, Nakrani R. Six children with allergic contact dermatitis to methylisothiazolinone in wet wipes (baby wipes). Pediatrics. 2014;133:e434-e438.

11. Gul U, Gonul M, Kaya I, et al. Autoimmune thyroid disorders in patients with psoriasis. Eur J Dermatol. 2009;19:221-223.

12. Prahalad S, McCracken C, Ponder L, et al. A120: Familial autoimmunity in the CARRA registry. Arthritis Rheumatol. 2014;66(suppl 11):S157.

13. Mercy KM, Paller AS. The relationship between obesity and psoriasis in the pediatric population: implications and future directions. Cutis. 2013;92:107-109.

14. Paller AS, Mercy K, Kwasny MJ, et al. Association of pediatric psoriasis severity with excess and central adiposity: an international cross-sectional study. JAMA Dermatol. 2013;149:166-176.

15. Becker L, Tom WL, Eshagh K, et al. Excess adiposity preceding pediatric psoriasis. JAMA Dermatol. 2014;150:573-574.

16. Volf EM, Levine DE, Michelon MA, et al. Assessor-blinded study of the metabolic syndrome and surrogate markers of increased cardiovascular risk in children with moderate-to-severe psoriasis compared with age-matched population of children with warts. J Drugs Dermatol. 2011;10:900-901.

17. Manzoni AP, Weber MB, Nagatomi AR, et al. Assessing depression and anxiety in the caregivers of pediatric patients with chronic skin disorders. An Bras Dermatol. 2013;88:894-899.

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19. Posso-De Los Rios CJ, Pope E, Lara-Corrales I. A systematic review of systemic medications for pustular psoriasis in pediatrics. Pediatr Dermatol. 2014;31:430-439.

20. Tollefson MM. Diagnosis and management of psoriasis in children. Pediatr Clin North Am. 2014;61:261-277.

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22. Windschall D, Müller T, Becker I, et al. Safety and efficacy of etanercept in children with the JIA categories extended oligoarthritis, enthesitis-related arthritis and psoriasis arthritis [published online ahead of print July 18, 2014]. Clin Rheumatol. 2015;34:61-69.

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Psoriasis affects 2% to 4% of the US population, with approximately one-third of cases beginning in childhood. The understanding of pediatric psoriasis has developed at a far slower pace than adult disease, with limitations in care including few medications that are approved by the US Food and Drug Administration for pediatric and adolescent use. Recently, a stable fixed-combination dose of calcipo-triene 0.005%–betamethasone dipropionate 0.064% topical suspension was approved for treatment of plaque psoriasis of the scalp in patients aged 12 to 17 years, which hopefully will lead a trend in psoriasis medication approval for children and teenagers.¹ Based on a PubMed search of articles indexed for MEDLINE using the search terms pediatric psoriasis, psoriasis, and strep that were published from April 2012 to April 2014, this article reviews newer data to address the issues that surround pediatric psoriasis and to provide an update on prior review articles on pediatric psoriasis.^2-5 This article reviews some of the newer literature on clinical presentation and comorbidities in pediatric psoriasis.⁵ Based on these recent findings, additional screenings including review of obesity parameters are recommended for pediatric patients with psoriasis (Table 1).

Update on Disease Manifestations, Associations, and Comorbidities

Disease Manifestations

A 2013 multicenter study delineated the clinical features of pediatric psoriasis.⁶ The study was conducted at 8 geographically diverse dermatology clinics in the United States to delineate the clinical manifestations of pediatric psoriasis. In an assessment of 181 participants aged 5 to 17 years, the investigators sought to determine the frequency of disease sites, severity, and guttate disease. Over a period of approximately 2 years, 43.1% of participants were determined to have mild disease and 56.9% had severe disease. Family history of psoriasis was present in 51.4% of participants, with first-degree relatives affected in 59.8% of cases. Scalp involvement at some time was noted in 79.0% of participants, and nail disease was noted in 55% of boys and 29% of girls. Guttate psoriasis was noted in 30% of participants, with more cases in the severe range (35.9%) versus the mild range (21.8%). Additionally, 22.1% of participants had a precipitating streptococcal infection, with the association being more common in pediatric patients with guttate psoriasis than plaque psoriasis.⁶ This study highlighted that pediatric psoriasis has a genetic basis, is frequently guttate in nature, commonly affects the nails, shows a trend toward being classified as severe, and may be triggered by streptococcal infections.

Streptococcal Infection

Pediatric psoriasis may be triggered or flared by Streptococcus pyogenes (group A β-hemolytic streptococci) infections, specifically β-hemolytic streptococci groups A, C, and G that have streptococcal M protein,^2,3,7 and this tendency can be associated with HLA-Cw6 or guttate psoriasis. Newer data have elucidated the role of streptococcal throat infections in psoriasis. Given that streptococcal throat infections are most common in school-aged children, these studies suggest a putative mechanism in pediatric psoriasis for triggering streptococcal infections, which would need to be confirmed in future studies, specifically in pediatric psoriasis patients.

It has been shown that T cells in psoriasis patients recognize common streptococcal M proteins and keratin determinants.⁷ Ferran et al⁸ recently demonstrated activation of circulating cutaneous lymphocyte–associated antigen (CLA)⁺ T cells but not CLA^- memory T cells in 27 psoriasis patients (ages not specified) when mixed with streptococcal throat extracts, causing production of IL-17, IP-10, IL-22, and IFN-γ; activation was not found in 6 healthy control patients. Antistreptolysin O levels were correlated with the messenger RNA up- regulation for IL-17, IP-10, IL-22, and IFN-γ, and also correlated with psoriasis area and severity index score in psoriasis patients. In this same study, injection of the activated culture supernatant into mouse skin caused epidermal hyperkeratosis and activation of nonlesional epidermal cells from psoriatic patients. This study thereby delineated some of the potential pathways of the streptococcal induction of psoriasis and psoriatic flares in childhood⁸; however, confirmation is needed through further study of pediatric psoriatic lymphocyte activity.

Differential Diagnosis

Additions to the extensive differential list have been cited in the recent literature. The differential diagnosis of pediatric psoriasis now includes sodium valproate–induced psoriasiform drug eruption⁹ and allergic contact dermatitis to methylchloroisothiazolinone and methylisothiazolinone, which are present in many sanitizing hand and diaper wipes and has been reported to cause psoriasiform dermatitis in a periorificial or perineal distribution.¹⁰ Clinicians should inquire about the use of these wipes, as caregivers rarely suspect this agent to be causative of the eruption.

Psoriatic Arthritis

Previously, psoriasis and psoriatic arthritis have been linked to autoimmune thyroid disease in adults.¹¹ A study of the Childhood Arthritis & Rheumatology Research Alliance (CARRA) registry showed that family history of psoriasis, autoimmune thyroiditis, Crohn disease, and ankylosing spondylitis in a first-degree relative has been linked to juvenile idiopathic arthritis, highlighting that pediatric psoriasis can be genetically linked or associated with multiple autoimmune conditions and vice versa.¹²