What Is Causing This 5-Year-Old’s Itchy, Scaly, Pink Plaques?
A 5-year-old girl presented with a 3-week history of multiple discrete, pink, scaly plaques. The plaques were ovoid, ranged from 0.5 to 3 cm in diameter, and were slightly raised, blanchable, and pruritic. The lesions were most appreciated over her right arm, where they coalesced into an erythematous, linear, raised plaque of 15 to 18 cm in length. Lesions also were appreciated over the scalp, arms, and legs bilaterally, as well as the torso, with greater involvement of the dorsal aspect.
The parents denied any history of asthma or allergies in the girl, but noted that she had a history of eczema as an infant. Family history was negative for psoriasis.
The lesions had begun on her right shoulder after an episode of pharyngitis and upper respiratory infection that had been treated conservatively.
What do you suspect is causing these lesions?
A. Guttate psoriasis
B. Pityriasis rosea
C. Inflammatory linear verrucous epidermal nevus
D.Nummular eczema
(Answer and discussion on next page)
Answer: Guttate Psoriasis
A 5-year-old girl presented with a 3-week history of multiple discrete, pink, scaly plaques. The plaques were ovoid, ranged from 0.5 to 3 cm in diameter, and were slightly raised, blanchable, and pruritic. The lesions were most appreciated over her right arm, where they coalesced into an erythematous, linear, raised plaque of 15 to 18 cm in length (A). Lesions also were appreciated over the scalp, arms, and legs bilaterally, as well as the torso, with greater involvement of the dorsal aspect.
The parents denied any history of asthma or allergies in the girl but noted that she had a history of eczema as an infant. Family history was negative for psoriasis.
The lesions had begun on her right shoulder after an episode of pharyngitis and upper respiratory infection that had been treated conservatively.
The girl also was seen at a pediatric emergency department and had been treated with permethrin 5% cream for a presumed scabies infestation, but with no changes in the lesions. At follow-up, she had persistent pruritic lesions; rapid streptococcal antigen test results were negative, antistreptolysin O titer was elevated at 978 IU/mL, and throat culture was positive for group A streptococcus.
Histologic results of a right arm lesion biopsy demonstrated neutrophils at the summits of parakeratotic scales, with suprapapillary epidermal plate thinning, a superficial perivascular infiltrate, and a focal area of hypogranulosis (B).
This girl’s clinical presentation and the histologic findings were consistent with a diagnosis of guttate psoriasis with a linear involvement.
The patient was treated with amoxicillin and topical mupirocin for 10 days and was scheduled for a 3-month follow-up visit. She had developed several hypochromic lesions with lichenification, which were improving at the 3-month visit.
Discussion
Guttate psoriasis is a common form of psoriasis in children that presents with a generalized and diffuse distribution. It often develops 1 to 3 weeks after an upper respiratory infection, typically streptococcal pharyngitis.1 Rapid strep tests often demonstrate positive antistreptolysin O titers.
The main differential diagnosis is pityriasis rosea, which can be differentiated from guttate psoriasis by way of the patient’s overall history, a history of a herald patch, the characteristic Christmas tree configuration on the trunk, and the appearance of a collarette of fine scales.
No clear evidence supports the effectiveness of antibiotic treatment of guttate psoriasis, which usually is self-limited but does carry a risk of evolving into a chronic form of psoriasis.2
Linear psoriasis is a rare variant of psoriasis that is characterized by psoriatic lesions along the lines of Blaschko. The main differential diagnosis for linear psoriasis is inflammatory linear verrucous epidermal nevus, which often is present in the first months of life, is highly pruritic, and is resistant to antipsoriatic therapies, in contrast to linear psoriasis, which has a later onset, typically is asymptomatic, and responds well to therapy. The pathogenesis of linear psoriasis is unclear but may include a component of genetic mosaicism.3 n
Rogerio Faillace, MD, is an assistant professor of pediatrics at Nova Southeastern University College of Osteopathic Medicine in Fort Lauderdale, Florida.
Miguel Villacorta, BS, is a fourth-year medical student at Nova Southeastern University College of Osteopathic Medicine.
Fawn Winkelman, DO, is a clinical assistant professor of family medicine at Nova Southeastern University College of Osteopathic Medicine.
Elyse Julian, BS, is a fourth-year medical student at Nova Southeastern University College of Osteopathic Medicine.
References
1. Farber EM, Nall L. Childhood psoriasis. Cutis. 1999;64(5):309-314.
2. Browning JC. An update on pityriasis rosea and other similar childhood exanthems. Curr Opin Pediatr. 2009;21(4):481-485.
3. Brinca A, Santiago F, Serra D, Andrade P, Vieira R, Figueiredo A. Linear psoriasis – a case report. Case Rep Dermatol. 2011;3(1):8-12.