History

Fact Explanation
Skin lesions with pruritus, burning and irritation This is seen due to inflammatory changes of the skin. Burning and irritating sensation are not common [1].
History of precipitating factors Infection by streptococcus (sore throat) as a precipitating factor is seen more in Guttate psoriasis than in other types of psoriasis [2]. Other factors are trauma, drugs, vaccination and emotional factors [3]. Drugs include antimalarials and steroids. These factors activate the immune system and enhance keratinocyte proliferation [4].
Family history of psoriasis Due to genetic susceptibility. HLA genes are thought to be involved in the pathogenesis [4]. Psoriasis in a first degree relative is seen in more than 50% of patients [2].
Joint symptoms Pain/ swelling/ erythema of distal interphalangeal joints, shortening of fingers due to arthritis mutilans, back pain and buttock pain due to sacroileitis and ankylosing spondylitis are manifestations of psoriatic arthritis. This is seen in 1% of children with psoriasis [4].
Eye symptoms (pain/ redness/ blurring of vision/ tearing) Occurs due to associated uveitis, conjunctivitis or episcleritis [4].
References
  1. NANDA, Arti, Surrinder KAUR, Inderjeet KAUR, Bhushan KUMAR. Childhood Psoriasis: An Epidemiologic Survey of 112 Patients. Pediatric Dermatology [Online]. John Wiley and sons. March 1990, 7(1),19-21 [viewed 28 March 2014]. Available from: doi: 10.1111/j.1525-1470.1990.tb01067.x.
  2. MERCY, Katherine,Mary KWASNY, Kelly M. CORDORO, Alan MENTER et al. Clinical Manifestations of Pediatric Psoriasis: Results of a Multicenter Study in the United States. Pediatric Dermatology [Online]. John Wiley and sons. July/August 2013, 30(4), 424-28 [viewed 25 March 2014]. Available from: doi: 10.1111/pde.12072.
  3. MORRIS, Anne, Maurine ROGERS, Gayle FISCHER, Katrina WILLIAMS. Childhood Psoriasis: A Clinical Review of 1262 Cases. Pediatric Dermatology [Online]. John Wiley and sons. May/June 2001, 18(3), 188-98 [viewed 25 March 2014]. Available from: doi: 10.1046/j.1525-1470.2001.018003188.x.
  4. MALLORY, Susan Bayliss. Illustrated Manual of Pediatric Dermatology: Diagnosis and Management. 1st ed. United Kingdom: Taylor & Francis, 2005.

Examination

Fact Explanation
Skin lesions: plaque psoriasis Pink plaques with silvery scales on extensor/ flexor surfaces, lower back, ears and scalp. Involvement of the frontal hairline, gluteal cleft, axillae, inguinal creases and perineum can also be seen [1].
Skin lesions: Guttate psoriasis Commonly seen in children. Small 'rain-drop' like circular/oval plaques appear abruptly on the back, often following streptococcal infection [2].
Skin lesions: Infantile psoriasis Lesions are seen in the skin folds including the diaper area, face, scalp, periumbilical area, palms & soles in infants [1].
Skin lesions: Pustular psoriasis Lesions contain pustules with erythema and desquamation [1].
Koebner phenomenon New psoriatic plaques develop at the sites of trauma [2].
Nail changes T cell mediated enhanced keratinocyte proliferation leads to nail changes. Most common feature is pitting. Others include discoloration, oil spotting, distal subungual debri formation and onycholysis [1].
Psoriatic arthritis Swollen, tender, erythamatous joints are seen due to inflammatory changes brought by the activated immune system.
References
  1. MALLORY, Susan Bayliss. Illustrated Manual of Pediatric Dermatology: Diagnosis and Management. 1st ed. United Kingdom: Taylor & Francis, 2005.
  2. KUMAR, Praveen, Michael CLARK. Kumar & Clark's clinical medicine. 7th ed. Spain: Elsevier, 2009.

Differential Diagnoses

Fact Explanation
Seborrheic dermatitis Produces scaly scalp lesions similar to scalp psoriasis in infants. Scales are thick and greasy known as the 'cradle cap' [1]. The face is involved more commonly unlike in psoriasis [2].
Onychomycosis Nail changes similar to psoriasis occur by fungal infection. KOH mount is useful to distinguish this from psoriasis [1].
Napkin candidiasis Involves the diaper area similarly to infantile psoriasis. The lesions are sharply defined erythematous, scaly plaques with satellite papules [2].
Atopic dermatitis Skin lesions can invove the whole body including the scalp. The distinguishing feature from psoriasis is severe pruritus [2]. Note: Some children with atopic dermatitis develop psoriasis after some years as well as some with psoriasis develop atopic dermatitis later [2]. This may be due to defects in the function of the immune system as seen in both conditions.
Pityriasis rosea Produces round, pink, scaly skin lesions over the trunk similar to guttate psoriasis. The size of the lesions are smaller than in guttate psoriasis [2].
Tinea corporis Produces skin lesions similar to psoriasis in the inguinal area. KOH examination is useful in differentiating the lesions [1].
Erythroderma This may be mistaken for early onset psoriasis with widespread involvement. Erythroderma produces red, thick, scaly skin with severe pruritus [2]. Skin color is bright red and involve a major part of the body unlike in psoriasis .
Pityriasis rubra pilaris Produces reddish-orange papules follwed by scaling. Nail changes also occur including discoloration of the nail and subungual hyperkeratosis [1]. Skip lesions (islands of normal skin) are more suggestive of pityriasis rubra pilaris [2].
References
  1. WOLFF, Klaus. Richard Allen JOHNSON. Fitzpatrick’s Color atlas and synopsis of clinical dermatology. 6th edition. Singapore: McGraw-Hill, 2009.
  2. JANNIGER, C.K., R.A. SCHWARTZ, M.L. MUSUMECI, A. TEDESCHI et al. Infantile psoriasis. Cutis [Online]. Fronyline Medical Communocations. September 2005, 76,173–7 [viewed 29th March 2014].

Investigations - for Diagnosis

Fact Explanation
Histology of the skin lesions Shows epidermal hyperplasia, thinned out granlar layer, parakeratosis, intracorneal and intraepidermal neutrophils, perivascular lymphocytic infiltrate and dilated dermal capillaries with mild erythrocyte extravasation. Note: Psoriasis is an essentially clinically diagnosis, made on the typical appearance of the skin lesions. Histology can be used when there is diagnostic uncertainity [1].
KOH examination Used to exclude tinea/ candida infections giving rise to similar skin lesions of psoriasis, commonly in the inguinal region & nails [2].
Investigations for streprococcal infection: Antistreptolysin titre & throat cultre Increased antistreprolysin titre is sometimes seen in acute guttate psoriasis, as streptococcal infection acts as a triggering factor for acte guttate psoriasis. Throat culture for group A beta haemolytic streptococcus also supports in making the diagnosis [2].
References
  1. MALLORY, Susan Bayliss. Illustrated Manual of Pediatric Dermatology: Diagnosis and Management. 1st ed. United Kingdom: Taylor & Francis, 2005.
  2. WOLFF, Klaus. Richard Allen JOHNSON. Fitzpatrick’s Color atlas and synopsis of clinical dermatology. 6th edition. Singapore: McGraw-Hill, 2009.

Management - General Measures

Fact Explanation
Patient education and counselling Explaining the child and the parents about the chronic course of the disease, possibility of relapses even with medication, and about the triggering factors will help to cope with the disease well with minimal exacerbations [1].
References
  1. ROGERS, M., Childhood psoriasis. Currunt Opinion in Pediatrics [Online]. Ovid Technologies.2002, 14, 404-9 [viewed 25 March 2014].

Management - Specific Treatments

Fact Explanation
Tar preparations Preparations like anthralin, liquor picis carbonis are good for children as they are safe for long term use and less likelihood of relapse once termination of treatment. Important: these preparations can be irritants to infants, and to any age when applied over the face & other sensitive areas [1].
Calcipotriol This is a synthetic derivative of vitamin D, effective in treatment of childhood psoriasis on long term. Important: It is recommended to monitor vitamin D metabolites level during the treatment as calcipotriol may reduce the endogenous synthesis of vitamin D [2].
Topical immunomodulators: tacrolimus, pimecrolimus These act by inhibiting cytokine production and thereby suppressing the immune activity. Very effective mode of treatment for psoriasis in children. Can be applied safely to face and intertriginous areas, unlike steroids [3].
Steroids Effective treatment mode for plaque type psoriasis [4]. However, the side effect profile is high with cutaneous atrophy and stunting, and cannot be used for sensitive areas such as face and genitals [3].
Phototherapy Ultraviolet B and psoralin Ultraviolet A (PUVA) are effective in treatment [5]. Most common side effect is erythema. Other effects include burning, pruritus and xerosis that last only for a short term [6]. It is Important to note that oral PUVA is not recommended for children under 11 years of age, topical PUVA is a good treatment option for them [5].
Systemic therapy with methotrexate, cyclosporin and retinoids Effective for severe disease [5]. Methotrexate causes nausea and vomiting most commonly, while fibrotic changes in the liver can be induced on long term use. Use of oral retinoids for long term can cause stunting in children by premature ossification of epiphyses [7].
References
  1. ROGERS, M., Childhood psoriasis. Currunt Opinion in Pediatrics [Online]. Ovid Technologies.2002, 14, 404-9 [viewed 25 March 2014].
  2. PARK, S. B., D. H. SUH, J. I. YOUN. A Pilot Study to Assess the Safety and Efficacy of Topical Calcipotriol Treatment in Childhood Psoriasis. . Pediatric Dermatology [Online]. John Wiley and sons. July/August 1999, 16(4), 321-5 [viewed 25 March 2014]. Available from: doi: 10.1046/j.1525-1470.1999.00084.x
  3. BRUNE, Adriana, Drew W. MILLER, Peggy LIN, Daniela COTRIM-RUSSI et al. Tacrolimus Ointment is Effective for Psoriasis on the Face and Intertriginous Areas in Pediatric Patients. Pediatric Dermatology [Online]. John Wiley and sons. January/February 2007, 24 (1), 76-80 [viewed 30 March 2014]. Available from: doi: 10.1111/j.1525-1470.2007.00341.x
  4. WOLFF, Klaus. Richard Allen JOHNSON. Fitzpatrick’s Color atlas and synopsis of clinical dermatology. 6th edition. Singapore: McGraw-Hill, 2009.
  5. MALLORY, Susan Bayliss. Illustrated Manual of Pediatric Dermatology: Diagnosis and Management. 1st ed. United Kingdom: Taylor & Francis, 2005.
  6. ERSOY-EVANS, Sibel, Aslı ALTAYKAN, Sedef S. AHIN, Fikret Ko¨LEMEN, Phototherapy in Childhood. Pediatric Dermatology [Online]. John Wiley and sons. November/December 2008, 25 (6), 599-605 [viewed 30 March 2014]. Available from: doi: 10.1111/j.1525-1470.2008.00773.x
  7. KUMAR, Bhushan, Sandipan DHAR, Sanjeev HANDA, Inderjeet KAUR. Methotrexate in Childhood Psoriasis. Pediatric Dermatology [Online]. John Wiley and sons. September 1994,11(3), 271-3 [viewed 30 March 2014]. Available from: doi: 10.1111/j.1525-1470.1994.tb00602.x.