Pediatrics

Psoriasis

OVERVIEW: What every practitioner needs to know

Are you sure your patient has psoriasis? What are the typical findings for this disease?

Erythematous plaques with white, micaceous scale over extensor surfaces of large joints, face, scalp, buttocks, umbilical area.

Variable itchiness, but not infrequent, for example, on affected scalp areas.

In newborns, babies: diaper area may present with shiny erythema with little or no scale.

Other presentations:

guttate (small, rather diffuse, drop-sized plaques); pustular (minute sterile pustules on erythematous base); erythrodermic (very little or no scale); inverse (in intertriginous areas); ungual (oil spots, pitting, subungual hyperkeratosis); mucosal (glossitis, lingua geographica); psoriatic arthritis

Other clinical characteristics

Koebner phenomenon: occurrence of lesions in areas of trauma. Auspitz sign: pinpoint bleeding at base of removed scale

Special clinical presentation

Congenital psoriasis: involving face, scalp, chest, trunk, sparing the buttocks.

Psoriasis-eczema overlaps if both conditions coexist or if psoriasis plaques are very irritated and superimposed by eczema.

Annular pustular psoriasis: most common form of pustular psoriasis in childhood, often affecting lower extremities.

Familial juvenile generalized pustular psoriasis: extremely rare.

What other disease/condition shares some of these symptoms?

Differential diagnoses:

Plaque type: atopic/nummular dermatitis, tinea, pityriasis rubra pilaris (PRP)

Guttate type: pityriasis rosea, parasporiasis, tinea, PRP

Pustular: bacterial, fungal (yeast, tinea) or herpes infection, acute generalized exanthematous pustulosis (AGEP)

Erythrodermic: PRP, eczema, staphylococcal scalded skin syndrome, cutaneous T-cell lymphoma/mycosis fungoides

Inverse: Intertrigo, erythrasma, tinea

What caused this disease to develop at this time?

  • Autoimmune condition with strong genetic association and familiarity, but sporadic occurrence is also possible and common.

  • Polygenic disorder with strong HLA-association, mainly with HLA-Cw6. With both parents affected, risk for offspring is 65%; if in addition a sibling is affected, the risk rises to 83%.

  • Shares genetic susceptibility loci with Crohn's disease and ulcerative colitis.

  • Shares some pathogenetic background with atopic dermatitis through filaggrin mutations that are observed in both conditions.

  • Bacterial infections, mainly streptococcal and typically of upper respiratory tract, can cause disease onset or flare/worsening.

  • 2% to 3.5% of the general population suffer from psoriasis. Accounts for 4% of all dermatoses in children under age 16.

  • Approximately 1/3 of psoriasis patients experience disease onset in early childhood

  • Early disease onset is twice as common in girls than boys

  • Physical injury or trauma provokes lesions to develop at site of impact (Koebner phenomenon)

What laboratory studies should you request to help confirm the diagnosis? How should you interpret the results?

  • Skin biopsy usually helps to confirm the diagnosis in doubtful cases (limitation: a fresh psoriatic lesion and acute eczema can share histologic features)

  • Bacterial and fungal cultures from pustules are sometimes needed to sort out pustular psoriasis.

Would imaging studies be helpful? If so, which ones?

  • Imaging studies: standard x-ray imaging usually needed for work-up of suspected psoriatic arthritis. Normally ordered by pediatric rheumatologists, who should become involved in the care for those cases.

Confirming the diagnosis

  • In infants and young children, the psoriatic lesions often present on scalp and face (the face being much less commonly affected in adults).

  • In psoriatic diaper eruption, the lesions are typically bright red and shiny, well demarcated, and involve the groin folds. They respond poorly to conventional diaper dermatitis therapy.

  • Localized, limited variants of psoriasis tend to prefer the scalp, the genital area, palms and soles, flexural areas, the umbilicus, and the nails.

If you are able to confirm that the patient has psoriasis, what treatment should be initiated?

  • Treatment should be targeted against the predominant type of presentation, i.e., plaque, pustular, erythrodermic, palmoplantar, etc.

  • Due to the lack of systematic large-scale studies in the pediatric population for most of the treatments, the first step should always attempt to be a topical regimen.

  • Eventual underlying factors or triggering conditions (e.g., infectious processes, stress, trauma) should be addressed and treated in parallel (e.g., guttate psoriasis, a not uncommon manifestation in childhood age that is typically triggered by preceding or concomitant infection; usually responds well to a two-week course of an oral macrolide antibiotic +/- phototherapy).

  • Topical corticosteroids: first-line treatment for all age groups. Choice of potency class and vehicle depends on anatomic area, severity of inflammation.

  • If lesions are highly hyperkeratotic, a keratolytic pretreatment with salicylic acid in concentrations between 5% and 15% over several days can be very helpful to ease the penetration of subsequently applied topicals.

  • Topical vitamin D analogues (calcitriol/calcipotriol, calcipotriene, tacalcitol): steroid alternative and complementing substances for intertriginous/flexural areas, can be combined with any other treatment except for salicylic acid preparations that inactivate them.

  • Topical coal tar

  • Topical tazarotene

  • Topical anthralin (dithranol)

  • Topical calcineurin inhibitors

  • Phototherapy / laser

  • Systemic retinoids

  • Systemic methotrexate

  • Systemic cyclosporin

  • Systemic biologics

  • Combination treatments

  • Long-term management can include several options: phototherapy, intermittent use of topicals, systemic treatment

  • 308 nm excimer lamp or laser: very good option for smaller lesions where a more targeted treatment is desired. Otherwise comparable to UVB narrowband (311 nm).

What are the adverse effects associated with each treatment option?

Topical corticosteroids: skin atrophy, discoloration, hypertrichosis, steroid acne, vasoconstriction. Tachyphylaxis can occur with prolonged continuous use.

Topical salicylic acid: systemic toxicity if absorbed in excess amounts through large areas of skin. The risk is highest in very young infants who have a relatively large body surface.

Topical vitamin D analogues: local irritation, hypercalcemia

Topical coal tar: local irritation, increased sun sensitivity

Topical tazarotene: local irritation, increased sun sensitivity, dry/peeling skin

Topical anthralin (dithranol): local irritation, increased sun sensitivity

Topical calcineurin inhibitors: local irritation, increased sun sensitivity

Phototherapy / laser: irritation, erythema

Systemic retinoids: dryness of skin and mucosal surfaces (cheilitis), pruritus, hair loss, sun sensitivity, headaches, joint and muscle pain, hepatotoxicity, dyslipidemia, inhibition of bone growth

Systemic methotrexate: gastrointestinal upsets, nausea, oral ulceration, increased risk of infection, cytopenia, cumulative hepatotoxicity, interstitial pneumonitis

Systemic cyclosporin: immunosuppression / increased risk of infection, nephrotoxicity, hypertrichosis, gingival hyperplasia, hyperlipidemia, headaches

Systemic biologics: injection site reactions, increased risk of infection, cytopenia, elevated liver enzymes, lupus-like syndrome, antibody formation to the medication

What are the possible outcomes of psoriasis?

Psoriasis is usually a chronic or chronically relapsing disease. However, in children there is a high rate of spontaneous improvement to even clearing.

Treatment should be kept topical as long as possible since it bears the smallest risk of serious side effects. This also includes phototherapy.

For plaque and guttate type psoriasis, the two most frequent clinical presentations in childhood age, phototherapy almost always constitutes an option to be considered in the treatment plan if logistically feasible (minimum of two sessions per week needed for reasonable effect).

Benefits of systemic management might be faster and more sustainable improvement and improved efficacy.

Systemic treatment inevitably plays a more important role in psoriatic arthritis. However, systemic treatments bear a higher risk of serious side effects in general.

Scalp involvement, nail dystrophy, and intergluteal/perianal psoriatic lesions are all associated with a higher risk for psoriatic arthritis.

Psoriasis bears an increased risk for metabolic syndrome and cardiovascular disease.

What causes this disease and how frequent is it?

  • Detailed epidemiology:

    • 2 %to 3.5% of the general population suffer from psoriasis.

    • Accounts for 4% of all dermatoses in children under age 16.

    • Approximately 1/3 of psoriasis patients experience disease onset in early childhood.

    • Equal sex distribution, but early onset more often seen in girls

  • Genetics: exact pathogenesis of psoriasis is still not known. Many genes are found to be involved: HLA-Cw6/-B57/-DR7, IL12B9, IL13, IL23R, STAT2, IL23A, TNFAIP3, TNIP1, PSORS1, HLA-C, PSORS6, CARD15, CYLD, TGM5, SCL12A8, FLG, IL1RN.

  • 23%-71% of children have positive family history of psoriasis.

  • Psoriasis is more common in identical (up to 72%) than fraternal (up to 30%) twins

  • Environmental noxa: smoking and alcohol consumption seem to have a deteriorating effect on the skin of adult psoriatic patients.

How do these pathogens/genes/exposures cause the disease?

  • Psoriasis is a T-cell mediated autoimmune condition. Infectious agents that can attract T-cells to the skin are found to be triggering factors.

  • Upper respiratory tract infections, throat and perianal streptococcal foci are common causes of disease onset.

  • Cross-reactivity of keratinocyte antigens with streptococcal antigens is thought to initiate the condition in setting where streptococcal infection present.

  • Other infectious agents noted in the context of psoriasis are staphylococci and human papillomavirus (HPV).

  • Guttate psoriasis is believed to be linked to an inflammatory (infectious) focus in about 2/3 of cases.

  • Concurrent autoimmune conditions described in childhood: morphea, vitiligo.

Other clinical manifestations that might help with diagnosis and management

In doubtful, less evident cases: check nails and tongue for typical changes

What complications might you expect from the disease or treatment of the disease?

Complications: psoriasis is more and more recognized as being a systemic, autoimmune inflammatory condition where different organs/organ systems can be or become affected and can cause problems such as coronary artery disease or high blood pressure. Metabolic syndrome seems to be present in a higher proportion in psoriatic patients compared with the non-psoriatic population. Preliminary results from studies on childhood psoriasis seem to be pointing in the same direction.

Psoriatic arthritis: rare, more frequent in girls than boys (3:2), manifesting typically around 9-12 years of age

Are additional laboratory studies available; even some that are not widely available?

Genetic studies (HLA typing: -Cw6, -B57, -DR7)

How can psoriasis be prevented?

Some experts advocate for a preventive removal of the tonsils due to the high association with streptococcal pharyngitis. This is controversial.

What is the evidence?

Bard, S, Torchia, D, Schachner, LA. "Managing pediatric patients with psoriasis". Am J Clin Dermatol. vol. 11. 2010. pp. 15-7.

(Concise review with emphasis on practical aspects of care in pediatric psoriasis patients)

Silverberg, NB. "Update on pediatric psoriasis, part 1: clinical features and demographics". Cutis. vol. 86. 2010. pp. 118-24.

(Parts 1+2 together: One of the most complete updates on pediatric psoriasis in recent years)

Silverberg, NB. "Update on pediatric psoriasis, part 2: therapeutic management". Cutis. vol. 86. 2010. pp. 172-6.

(Parts 1+2 together: One of the most complete updates on pediatric psoriasis in recent years)

Ståhle, M, Atakan, N, Boehncke, WH. "Juvenile psoriasis and its clinical management: a European expert group consensus". J Dtsch Dermatol Ges. vol. 8. 2010. pp. 812-8.

(European Consensus Panel's conclusions and recommendations on juvenile psoriasis: the "European perspective")

De Jager, ME, de Jong, EM, van de Kerkhof, PC, Seyger, MM. "Efficacy and safety of treatments for childhood psoriasis: a systematic literature review". J Am Acad Dermatol. vol. 62. 2010. pp. 1013-30.

(Important, very diligently performed compilation of psoriasis treatments and their safety profiles in the pediatric population)

Lara-Corrales, I, Xi, N, Pope, E. "Childhood psoriasis treatment: evidence published over the last 5 years". Rev Recent Clin Trials. vol. 6. 2011. pp. 36-43.

(Most recent compilation of childhood psoriasis treatments based on evidence in a 5-year retrospective)

Ongoing controversies regarding etiology, diagnosis, treatment

Some experts advocate for a preventive removal of the tonsils/amygdalae due to the high association with streptococcal pharyngitis. This is controversial.

The association with systemic conditions like hypertonia, cardiovascular disease, obesity, metabolic syndrome, and the impact of environmental noxa, in particular smoking and alcohol, are intensely discussed in the adult psoriatic population.

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