Saturday, December 16, 2006

Psoriasis

Dear Lisa,

My 1-1/2 year old daughter and 3-1/2 year old son both have rashes on their legs. It looks like it could be eczema, but I have psoriasis and psoriasis runs in my husband's family. Could it be that my kids have it too?

“Mom in N.J.”

Dear “Mom in N.J.”,

As you already know, Psoriasis is a chronic inflammatory skin condition that is characterized by well-defined round or oval plaques. The rash is caused by a hyperproliferation and abnormal differentiation of keratinocytes with an inflammatory cell infiltration. In other words there is an overgrowth of the cells of the skin. This subsequently causes abnormal skin cell growth and is accompanied by inflammation.

In children Psoriatic lesions appear on the scalp, trunk, extremities and face. In some cases Psoriasis occurs in the diaper area and presents as a diaper rash unresponsive to traditional therapy.(1) The lesions found in Psoriasis consist of a plaque with a thick silvery scale.

When the scale is removed the capillary tips are exposed and the trauma of the removal causes pin point bleeding. This is called the Auspitz sign and is characteristic of all types of psoriasis. (2) As compared to adults, the plaques found in children tend to be smaller and have a finer scale. (3)

Psoriasis affects an estimated 2-3 percent of the world's population with nearly 1/3 of the cases presenting in childhood. (4,5) It is an inherited disorder with more than 2/3 of the children with Psoriasis having a positive family history of the disease.(1) If one parent has Psoriasis, a child has about a 10 percent chance of having Psoriasis. If both parents have Psoriasis, a child has approximately a 50 percent chance of developing the disease. (5)

Although there is a genetic basis for the disease, there are environmental factors that can trigger the clinical expression of symptoms. These triggers include injury, emotional stress, infection, cigarette smoking, and certain prescription medications.(5,6) The prescription medications that have been known to trigger Psoriasis include; Indomethacin, Lithium, Antimalarials, Inderal and Quinidine.(5)

Bacterial and Fungal skin infections can aggravate a child's Psoriasis. Lesions may also appear where the skin has been scratched or at the site of a surgical wound.

Another characteristic of Psoriasis is the Kobner phenomenon. The Kobner phenomenon is the development of psoriatic lesions in a linear fashion at a site of an external trigger.(7) An example of this occurs when a child wears a belt that is too tight. The trauma to the skin can result in psoriatic lesions in a straight line where the belt applied pressure.

Guttate Psoriasis is another childhood manifestation of Psoriasis. Guttate Psoriasis presents as a generalized eruption occurring all over the body, sparing the palms and soles. The eruptions appear drop like, consisting of 3 to 7 mm papules with a fine white scale over the surface.

The development of this type of rash classically follows a case of Strep Throat, but may also occur in association with an upper respiratory infection or viral flu.(2) Guttate Psoriasis is often the first presentation of Psoriasis in the adolescent and the beginning of the life long struggle with the disease.(2)

Eczema on the other hand is much different from Psoriasis. Eczema is a chronic relapsing inflammatory skin condition. Most cases of Eczema begin before one year of age with ninety percent of the cases occurring before a child is 5 years old. This is much different from Psoriasis which tends to develop during the second decade of life. Psoriasis commonly first appears between the ages of 15 and 25, although it is possible to occur at any age. (5)

The skin of a child who has Eczema is leathery, dry and excoriated. The distribution of rash is typically in the flexor surfaces of the elbow and knee. Itching is a very prominent feature of Eczema. Actually, itching must be present in order to make the diagnosis of Eczema. (8) Psoriasis may be itchy in some children but not necessarily in all affected by the disease.

Eczema also has a genetic component. Children with Eczema usually have a family member with a history of Hay fever or Asthma. (9) If both parents have Eczema, eighty percent of their children will also suffer from the disease. (9) It is necessary to know a child’s complete medical and family history before the cause of a rash can be determined.

Your children are at risk for developing Psoriasis because both you and members of their father’s family have Psoriasis. Although, because of their young age, Eczema is the more likely cause of the rash. Psoriasis tends to develop in older children while Eczema typically begins during the earlier years.

Basically, the diagnosis depends on the appearance of the rash and a complete physical examination. Skin lesions that have definite borders are suggestive of Psoriasis. A more diffuse rash with no well defined border is consistent with Eczema. In addition, other characteristics of the rash need to be determined such as the distribution of the rash on the body and whether or not the rash is itchy.

It is important to know that Psoriasis and Eczema are not the only skin conditions that present with scaly patches or plaques. Scaly patches and plaques can be found in many pediatric skin disorders. Pityriasis rosea, fungal skin infections such as Ringworm, lichen planus, Syphillus, Lupus and Dermatomyositis are some examples of pediatric skin conditions that can present with scaling or patches.(5) The best way to determine the cause of your children’s rash is to have them examined by their Physician.

For more information about topics covered in this article you can read the following Pediatric Advice Stories:

Eczema

Ringworm

Diaper Rash

For more information about Psoriasis contact:

The National Psoriasis Foundation

References:
(1)Morris A, Rogers M, Fischer G, Williams K. Childhood psoriasis: a clinical review of 1262 cases. Pediatr Dermatol. 2001;18(3):188-198.
(2)Barber K. Psoriasis. Consultant for Pediatricians. 2006. May:285-288.
(3)Greco M, Chamlin S. An 18-month-old Girl with Chronic Diaper Dermatitis. Pediatric Annals. 2006. 35(2):79-84.
(4)Langley R, Krueger G, Griffiths C. Psoriasis: epidemiology, clinical features and quality of life. Ann Rheum Dis. 2005;6(Suppl 2):ii18-ii23.
(5)National Psoriasis Foundation. About Psoriasis. Available at: http://www.psoriasis.org/about/stats/. Accessed Dec 2006.
(6)Hunter JAA, Savin JA, Dahl MV. Psoriasis. Clinical Dermatology. 3rd ed. Malden, Mass:Blackwell Science. 2002:48-55.
(7)Kamat D. Psoriasis. Consultant for Pediatricians. 2006. February:113.
(8)Beers MH, Berkow R, Scaling popular diseases: The Merck Manual of Diagnosis and Therapy. 17th ed. Whitehouse Station,NJ: Merck Research Laboratories. 1999:816-820.
(9)Rosenthal M. Pediatricians treating more patients with atopic dermatitis. Infectious Disease in Children. 2006. April:56.


Lisa-ann Kelly R.N., P.N.P.,C.
Certified Pediatric Nurse Practitioner

Pediatric Advice for Toddlers

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