Table 1.

Clinical variants of psoriasis vulgaris in childhood

Type of psoriasis	Typical clinical appearance	Diagnostic features and tests	Co-morbidities	Differential diagnosis	Treatment considerations
Plaque-type psoriasis	Erythematous plaques with micaceous scale in typical areas: Scalp extending to forehead, postauricular, elbows, knees, umbilical and buttocks	Clinical diagnosis can generally be made. Nail pitting can be noted as a clue to the diagnosis of psoriasis in children. Biopsy when need will demonstrate thickened epidermis with neutrophils in the horny layer the spongiform pustules of Kogoj and the subcorneal microabscess of Munro (collections of neutrophils in the epidermis)	Recent pharyngitis, specifically with Streptococcus, may precipitate disease. Pharyngeal bacterial culture or ASO testing can be helpful. Secondary infection with S. aureus can be noted. Other forms of autoimmunity can be seen. in the setting of obesity, disease severity can be a marker of cardiovascular risk	Nummular dermatitis Tinea capitis ID reaction Pitytriasis rubra pilaris Lichen planopilaris Atopic dermatitis (overlap can rarely be seen)	Treatments must be tailored to the age of the patient, quality of life issues, and surface area affected. Systemic agents and phototherapy may be needed in moderate to severe disease
Guttate psoriasis	Annular localized erythematous to salmon colored plaques with hyperkeratosis, sometimes micacous. Commonly noted on the trunk, abdomen and back	Clinical diagnosis is often possible. Biopsy is similar to that of plaque-type psoriasis	Recent pharyngitis, specifically with Streptococcus may precipitate disease. Pharyngeal bacterial culture or ASO testing can be helpful	Nummular dermatitis Pityriasis rosea ID reaction Tinea corporis Pitytriasis rubra pilaris	Oral antibiotics are often used initially due to presumptive infectious precipitating factors and for anti-inflammatory capabilities (erythromycin, cephalosporins). Systemic agents and phototherapy may be needed in moderaqte to severe disease.
Inverse psoriasis	Localization of erythematous, sometimes macerated thick plaques to the folds of the skin, including axillae and groin. Can be associated with plaque type psoriasis in other sites	Although clinical diagnosis is often possible, similarity to other diseases may require biopsy for differentiation	Secondary infection with Candida and/or Streptococcus may require cutaneous culture and usage of topical anti-infectives	Intertrigo Erythrasma Tinea corporis	Topical medications should be non-steroidal or low-potency topical corticosteroids to avoid atrophy of the occluded skin. Oral or topical anti-infectives should be added where appropriate
Nail psoriasis	Classic: Pitting, oil spots, subungual hyperkeratosis Trachyonychia: extensive pitting and subungual hyperkeratosis	Ruling out tinea infection or secondary candidal infection of the nail bed is needed when subungual hyperkeratosis is present. Fungal culture and nail plate biopsy	Secondary infections should be ruled out including pseudomonas, onychomycosis or candidal infections	Onychomycosis Lichen planus Pitytriasis rubra pilaris	After treatment of any fungal super-infection, topical corticosteroids with tazarotene or calcipotriene can be applied to the paronychial skin. Intralesional kenalog can also be used in the same region to reduce the subungual inflammation
Napkin or diaper psoriasis	Macerated shiny erythema of the groin region including the folds and the genital skin	Biopsy may need to be performed	Bacterial and fungal cultures may be needed for suspected secondary infections or perianal strep	Diaper dermatitis Candidal diaper dermatitis Allergic contact dermatitis	Mild topical corticosteroids with or without topical anti-candidal agents can be helpful Barrier therapy with zinc oxide pastes reduces secondary irritant reactions
Erythroderma	Generalized erythema and thickening of the skin, sometimes with hyperkeratosis	Two biopsies are generally required from separate sites to differentiate psoriatic erythroderma from other causes of erythroderma in childhood	Fever, chills and malaise can accompany erythroderma, making bacteremia a possible co-morbidity which should be ruled out conclusively	Causes of erythroderma in childhood include: Atopic dermatitis Pityriasis rubra pilaris Mycosis fungoides Staph scalded skin syndrome	Topical anti-inflammatory agents can be used, however, systemic anti-inflammatory agents (never steroids orally) are often required to control the severe and extensive disease
Pustular psoriasis	Erythroderma accompanied by sterile pustule formation, sometimes localized to the distal extremities, sometimes generalized. Prior history of oral steroid usage may be noted	Biopsy is often needed and bacterial culture of the pustules. ASO titers can be drawn to rule out streptococcal precipitant	Secondary bacterial infection or tinea should be ruled out	Blistering distal dactylitis Tinea infection with Tinea mentagrophytes Herpetic whitlow	Topical corticosteroids are often ineffective and systemic agents or topical PUVA may be needed
Mucosal/oral psoriasis	Annular plaques on the tongue may be noted in patients with psoriasis	Generally a clinical diagnosis	Rarely has any morbidity	Geographic tongue Aphthosis Lichen planus White sponge nevus	No therapy is usually needed, however topical medicaments in an oral base can be used when needed

Abbreviation: ASO, antistreptolysin O.