Pediatric Dermatology Consult

Pruritic, pink to violaceous, scaly papules

Publish date: October 15, 2019

A healthy 14-year-old female was referred urgently by her pediatrician to our pediatric dermatology clinic for evaluation of a rash. The rash had been present for 4 weeks on her torso and proximal extremities, and had been spreading. She had been very itchy. She denied any fevers, chills, joint pain, oral or genital lesions.

She was visiting some family members in Washington State during the summer. The rash started 1 month after this visit.
The adolescent had been treated with acyclovir, trimethoprim/sulfamethoxazole, and intramuscular triamcinolone without improvement. She had been taking children's multivitamins occasionally. Her vaccinations were up-to-date. She denied any history of varicella or herpes infection. Her mom has a history of cold sores. The teen is not sexually active.

On physical examination, the girl was not in acute distress. Her vital signs were stable. She was not febrile. She had pink, scaly, and hyperpigmented papules and plaques, some of which were crusted with violaceous centers on the trunk and proximal extremities. There were no lesions on the mouth, palms, or soles. She had no lymphadenopathy or hepatosplenomegaly.

A skin biopsy of one of the lesions was consistent with pityriasis lichenoides et varioliformis acuta (PLEVA).

Dr. Catalina Matiz

The patient was diagnosed with PLEVA, also known as Mucha-Habermann disease. This condition is a rare cutaneous disorder that affects mainly children and young adults. The true incidence of the condition is not known.

The typical presentation is an abrupt onset of pink to violaceous, scaly papules and plaques that later develop violaceous or necrotic centers, like the ones seen in our patient. The lesions more typically occur on the trunk and proximal extremities, but they may present in any other part of the body, rarely in the mucosa.¹ Some patients can develop the febrile, more severe form of PLEVA called febrile, ulceronecrotic Mucha-Habermann disease (FUMHD), which potentially can be life threatening.

Patients with PLEVA can complain of pruritus or a burning sensation, and in some cases can have associated arthralgia and edema. The more severe form FUMHD is characterized by persistent high fevers with associated internal organ involvement such as cardiomyopathy, small vessel vasculitis, abdominal pain, arthritis, pneumonitis, and hematologic abnormalities.² Mucosal involvement is a common finding in patients with FUMHD.

The pathogenesis of PLEVA is not very well understood. Some theories include a T-cell dyscrasia and an atypical immune response to an infection or vaccination.^3,4

The differential diagnosis of PLEVA includes varicella, pityriasis lichenoides chronica (PLC), lymphomatoid papulosis (LyP), disseminated herpes simplex infection, Gianotti-Crosti syndrome, and Langerhans cell histiocytosis.

Patients with varicella also present with lesions in different stages, similar to PLEVA, but the classic lesions are usually vesicular and described as dewdrops on a rose petal. The course of varicella is 1-2 weeks, compared with PLEVA where the lesions can be present for months to years.

Patients with PLC can have similar lesions to PLEVA, but the lesions rarely are necrotic. Some consider these two entities a spectrum of the same condition.⁵

LyP is a rare condition in children, and it is characterized by crops of pink papules and nodules that resolve within weeks. A skin biopsy may help distinguish between the two conditions because LyP lesions are characterized by atypical lymphocytes that are CD30 positive.

Children with Gianotti-Crosti syndrome present with papules and papulovesicles on the face, arms, buttocks, and legs, after an upper respiratory or GI infection. Sometimes the lesions may be hemorrhagic. Lesions resolve within weeks to months.

Hemorrhagic-crusted papules on a seborrheic and intertriginous distribution characterize Langerhans cell histiocytosis. These patients may present hepatosplenomegaly and lymphadenopathy – neither of which were present on our patient.

Children with mild PLEVA disease and who are not symptomatic may be followed without intervention. In those with more severe disease and who are symptomatic can be treated with tetracyclines such as minocycline or doxycycline or erythromycin for about 3 months.^6,7 Phototherapy also is recommended as a first-line therapy. In cases that do not respond to oral antibiotics and light therapy, methotrexate can be an alternative.

Dr. Matiz is a pediatric dermatologist at Southern California Permanente Medical Group, San Diego. Email her at pdnews@mdedge.com.