|Year : 2012 | Volume
| Issue : 1 | Page : 3-8
Childhood psoriasis - Clinical manifestations
Subash Lokre, Ravi Hiremagalore
Department of Pediatrics and Dermatology, Manipal Hospital, 98, HAL Airport Road, Bangalore, Karnataka, India
|Date of Web Publication||23-Oct-2012|
Department of Pediatrics and Dermatology, Manipal Hospital, 98, HAL Airport Road, Bangalore - 560 017, Karnataka
Source of Support: None, Conflict of Interest: None
Psoriasis is a chronic immune mediated inflammatory disease. It has different clinical patterns in childhood. It can vary from as simple as a napkin psoriasis to pustular and erythrodermic forms. The review discusses the epidemiology, trigger factors, clinical features of childhood psoriasis including the differential diagnosis of the various patterns.
Keywords: Psoriasis, childhood, clinical patterns
|How to cite this article:|
Lokre S, Hiremagalore R. Childhood psoriasis - Clinical manifestations. Indian J Paediatr Dermatol 2012;13:3-8
| Introduction|| |
Psoriasis is a chronic immune-mediated inflammatory disease most commonly manifested by well-demarcated erythematous plaques with silvery white scales on the elbows, knees, scalp and trunk. Childhood psoriasis is a well-recognized entity, but its true prevalence is not known. It differs in epidemiology, clinical features, treatment options, and long-term clinical and psychological outcome.  This article highlights the various clinical patterns of childhood psoriasis and their differential diagnosis. The authors would like to emphasize the fact that psoriasis should be considered in the differential diagnosis of some common childhood dermatoses.
| Epidemiology|| |
Psoriasis represents one of the most common skin conditions with an estimated prevalence of 1-3% worldwide. Psoriasis is a frequent condition in children, but only limited epidemiologic data are available. Various published large series have reported that of all psoriasis patients, 20 - 35% have onset of their disease before the age of 20 years.  It accounts for 4.1% of all dermatoses seen in children. 
In a study of 419 patients of childhood psoriasis from North India, it constituted 0.3% of all dermatology outpatients and 12.5% of the total psoriasis patients at a tertiary care hospital.  Psoriasis comprised 1.4% of all pediatric dermatoses seen in patients less than 14 years of age at a referral hospital in South India. 
The peak age of onset in childhood psoriasis varied in different studies. In surveys from India and Denmark, most patients developed first symptoms at the ages of 6 to 10 years, whereas other studies from the Middle East and Australia reported a peak of onset at the ages of up to 4 years. With regards to the sex predilection, studies from Denmark and Middle East have shown a female preponderance, but reports from India and Australia have documented equal sex predisposition. 
In children, there is a strong family history of psoriasis than in adults. Worldwide, there is an evidence of family history in 49-89% of cases where as in India, it is as low as 4.5 percent.  This could be related to lack of awareness of the condition in Indian patients or there were no cases in the family at the time of interview.
| Environmental Triggers|| |
Psoriasis can be precipitated by several environmental triggers such as Group A β-hemolytic streptococcal infections (GABHS),  trauma  and stress. GHABS infections have been reported to precipitate not only guttate psoriasis but also pustular forms of psoriasis in children.  Other infectious agents that have been reported in association with psoriasis include HIV, Pityrosporum folliculitis with guttate psoriasis  and candida albicans  Drugs have been reported to induce or exacerbate psoriasis in children, such as growth hormone, lithium, β-blocking agents, and recombinant γ and α-interferon.
| Clinical Features|| |
Clinical features are based on age of onset, family history and associated genetic markers.
It is classified into two types.
- Type I psoriasis, with an early onset, positive family history and association with HLA-Cw6, -B57 and DR7. Patients in this category tend to have more severe disease with large body areas involved and frequent recurrences 
- Type II psoriasis, with late onset (after 40 years), negative family history, and association with HLA-Cw2.
| Congenital and Infantile Psoriasis|| |
Psoriasis can rarely present in infancy. In a study involving 1262 cases of childhood psoriasis in Australia, about 16% of the patients were under one year of age. 
In infants, there are 2 patterns of clinical presentation:
- Psoriatic diaper rashes - Skin lesions in the diaper area has 2 distinctive patterns: Localized psoriatic diaper rash with well demarcated bright red rashes [Figure 1] and psoriatic diaper rash with dissemination where the initial presentation is well defined erythematous plaques localized to the diaper area slowly progressing to involve other areas. The differential diagnosis includes seborrheic dermatitis, irritant contact dermatitis and candida albicans infection. More sharply demarcated lesions, positive family history, presence of lesions in other areas and nail involvement favors the diagnosis of psoriasis. Also, regular follow up over a period of time to note the progression helps in making an accurate diagnosis.
- Psoriatic erythroderma - Psoriasis in infancy can rarely present as a nonspecific erythroderma [Figure 2]. This has been documented in 4% of 51 infants in a case series.  Clinically, scalp hyperkeratosis and nail involvement favors the diagnosis of psoriasis. However, other causes of erythroderma have to be differentiated which includes congenital non-bullous ichthyosiform erythroderma, atopic dermatitis, combined variable immunodeficiency and Nethertons syndrome. A skin biopsy may be needed to confirm the diagnosis.
| Childhood and Adolescence Psoriasis|| |
It is similar to adulthood psoriasis in many ways. As in adults, classical plaque psoriasis represents the most frequent clinical form in children. The initial manifestation of psoriasis if often triggered through an infection. The typical presentation in these cases is guttate psoriasis.
Psoriasis in children may present in the typical adult form of the classic plaque type of psoriasis. However, lesions are smaller, scales are often finer in children [Figure 3]. Areas of distribution are like in the adult form with a predilection to the extensor surfaces, knees, buttocks, elbows, and scalp. The frequency of plaque psoriasis in children varies from 34%- 84%. In dark skinned children, the scale may be so subtle that the condition presents as hypopigmentation, and the scale becomes obvious when the lesions are scratched. ,
Acute Guttate Psoriasis
It is an eruption of small papules in a widespread distribution, [Figure 4] often preceded by an intercurrent illness, usually a pharyngitis or tonsillitis due to group A β-hemolytic streptococci. Occurrence of acute guttate psoriasis has been reported with frequencies of 6.4- 44%. Streptococci were isolated from throat swabs in 33 out of 34 patients (97%) and serologic evidence of streptococcal infection was demonstrated in 56-85%. , Guttate psoriasis may later evolve into the classic plaque form or completely resolve in 3-4 months after elimination of triggering factors. This form of psoriasis has to be differentiated from pityriasis lichenoides chronic which may require a biopsy in some cases.
Micropapular or Follicular psoriasis
Small follicular papules of 1 to 2 mm size over the extensor aspects of the limbs are found particularly in the dark-skinned children [Figure 5]. Scratching these papules reveals white scale. This form is quiet common and needs to be differentiated from atypical pityriasis rubra pilaris (PRP).
Psoriatic involvement of the face is more common in children than in adults, and was found in 38% of children in a case series.  Lesions are erythematous, well defined and less itchy than eczematous patches [Figure 6]. Presence of lesions under the eye is common and often annular forms exist. Facial involvement in Indian children is as low as 4.71%. This could be due to the exposure to intense sunlight all the year around. 
The scalp is a common site of disease involvement at the onset and throughout the course of psoriasis. The clinical presentations are highly variable, ranging from mild to severe disease. It is characterized by thick silvery white scale on patches of erythema. It may extend beyond the hairline. Isolated scalp involvement is also common in children. Pityriasis amiantacea is a condition of the scalp characterized by thick yellow-white scales densely coating the scalp and adhering to the scalp hairs as they exit the scalp. They resemble flakes of asbestos and depending on the underlying disorder, the scalp skin may appear normal, or may be deeply erythematous. The condition is associated with hair loss and sometimes it is difficult to comb the hair due to the adherent thick scale at the base of hair shafts. Complications such as secondary bacterial infection can occur and hair loss may be associated with scarring. Tinea capitis is an important differential diagnosis, especially in children.
Inverse Flexural Psoriasis
Inverse psoriasis is located on genital, perianal, axillary, inguinal, or periumbilical areas. It usually appears as well-demarcated glazed erythematous lesions lacking the psoriatic scale. Local factors such maceration, bacterial or fungal infections may modify or aggravate psoriasis in these locations. 
Palmoplantar psoriasis comprises approximately 4% of all psoriasis in children. Presentation varies from thick scaling with fissuring to a glazed erythema. , This type of psoriasis is very common among Indian children which can be explained by the practices of walking barefoot and increased incidence of injuries [Figure 7]. Important differential diagnosis includes PRP, tinea pedis and dyshidrotic eczema. Lack of symptoms, nail changes and well demarcated lesions helps in the diagnosis. PRP can be differentiated on a biopsy.
Psoriatic Acral Dermatitis
This peculiar presentation of psoriasis was first described by Zaias in 1980. It is characterized by cutaneous involvement of the digits without the typical nail dystrophy of psoriasis. Features are erythema, scaling and fissures of the distal phalanges associated with shortening of the nail bed. 
Psoriatic nail changes have been reported in 7- 40% of children with psoriasis. Nail pitting (87%) was the most common change noted followed by onycholysis (10%), subungual hyperkeratosis (8%), and nail discoloration (5%) in one study.  It can be an isolated finding or associated with other forms of psoriasis [Figure 8].
Pustular psoriasis is rare and occurs more frequently in the adult population. Four forms have been described: Generalized pustular psoriasis [Figure 9], sub acute annular pustular psoriasis [Figure 10], palmoplantar pustular psoriasis [Figure 11] and pustular acrodermatitis of Hallopeau. The sub acute annular form is the most common form in children, and is characterized by annular plaques with a pustular margin.  Generalized pustular psoriasis of von Zumbusch is a type of acute erythroderma with diffuse pustules all over the body associated with high grade fever and constitutional symptoms. It resolves spontaneously with frequent recurrences as waves of pustules or the more classical plaque forms. It may be triggered by streptococcal infection. Localized pustular psoriasis of the palms and soles (acropustulosis) has been noted to occur rarely in children. It was found in 4.7% of childhood psoriasis cases in one study. 
| Mucosal Involvement|| |
Mucosal lesions were seen in 5.6% of children with psoriasis in one study.  Mucosal patches in oral or genital mucosa, oral erosions and geographic tongue were noted. It may cause a burning or stinging sensation after contact with certain foods, such as spicy or citrus foods.
| Psoriatic Arthropathy|| |
It is a rare condition in children. The peak age of onset is 9-12 years, and there is a slight female predominance.  The pattern of arthritis and course is similar to adults. The International League Against Rheumatism  has proposed the following diagnostic criteria for psoriatic arthropathy in children:
In general, skin lesions precede the onset of arthritis in 80% of cases. In children, psoriatic arthritis is initially oligoarticular involving mainly the proximal and distal interphalangeal joints of the feet and proximal interphalangeal joints of the hands and the knees and ankles. In the late stages, it tends to be polyarticular. Presence of blue discoloration over the affected joints is an important clinical clue to diagnosis. Juvenile idiopathic arthritis is an important differential diagnosis. The course of psoriatic arthropathy in children is unpredictable. However, prognosis is good with minimal disease activity in adulthood.
- Arthritis and psoriasis or,
- Arthritis and
- Family history of medically confirmed psoriasis in parents or siblings
- Nail abnormalities (pitting or onycholysis)
- Exclusions include positive rheumatoid test and presence of systemic arthritis.
Comorbidity of Psoriasis in Children
The overall rate of co morbidity in subjects with psoriasis aged less than 20 years was twice as high as in subjects without psoriasis. Childhood psoriasis was associated with increased rates of hyperlipidaemia, obesity, hypertension, diabetes mellitus, rheumatoid arthritis and Crohn disease. In a study examining children with at least one of 12 different skin diseases, children with psoriasis reported the greatest impairment to quality of life. Additionally, the study found that psoriasis impacts health related quality of life more than other chronic childhood conditions including epilepsy, diabetes and alopecia. 
The Psychosocial Impact of Psoriasis and Psoriatic Arthritis on Children
Nearly half of children with psoriasis reported being bullied in a survey conducted by the National Psoriasis Foundation. Children experience teasing, being excluded by peers, name calling, intimidation, and in some cases physical violence. The emotional impacts reported include anxiety, crying, trouble in school and difficulty in sleeping. Children with psoriasis face significant emotional and physical challenges. Compounding this, as in adults, individuals with psoriasis have an increased risk of depression, anxiety and suicidal tendencies. 
| Conclusion|| |
Psoriasis in children is not very rare and has varied clinical presentations. Each type should be differentiated from other common pediatric dermatoses. At times, skin biopsy may be needed to establish definitive diagnosis. Hence a strong index of suspicion and knowledge of the clinical patterns in children is needed for accurate diagnosis and management.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11]