Figure. Initial presentation shows small, scabbed lesions on back.
A 5-year-old boy of African and Hispanic descent presents to the office with sudden onset of small, scabbed lesions on his back. Over the next week, the lesions spread to cover the entire torso and portions of his arms and legs. The parents report that the boy has had mild pain and pruritus without fever, chills, or malaise. Examination reveals small reddish-brown macules that have progressed over the week to large, scaled plaques covering the majority of the body but sparing the face, palms, and soles.
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Pityriasis lichenoides et varioliformis acuta (PLEVA) is an acute form of pityriasis lichenoides that most commonly affects children and young adults.1 It is an inflammatory skin condition that is sometimes considered a lymphocytic vasculitis. Though the inciting event is unclear, preceding illness is noted in some cases such as cytomegalovirus, Epstein-Barr virus, or Toxoplasma gondii infection.4 Pityriasis lichenoides et varioliformis acuta tends to come on suddenly with spontaneous resolution occurring in weeks. The rash can recur and have a history of waxing and waning. The patient will otherwise feel well with mild itching; however, if systemic manifestations such as gastrointestinal complaints, central nervous system abnormalities, pneumonitis, or myocarditis occur, then the more severe form of PLEVA, known as Mucha-Habermann disease, should be considered. This form of PLEVA is a serious diagnosis and comes with a mortality rate of 20%.1-3
The lesions of PLEVA begin as erythematous macules or papules, 5 to 15 mm in diameter, that favor the trunk and upper extensors but can spread anywhere on the body and infrequently involve the palms and soles.2 The number of lesions can vary from just a few to a few hundred, and they evolve through stages of crusting, necrosis, and potentially scarring.⁵ Crops of lesions may appear at different times, which results in lesions of varying stages of healing.
A definitive diagnosis of PLEVA is established by biopsy. The biopsy will show epidermal necrosis with a wedge-shaped lymphocytic infiltrate in the upper and middle dermis, as well as perivascular lymphocytosis and parakeratosis.2-4 Although the lesions will likely regress on their own, treatment options for persistent or symptomatic PLEVA include oral erythromycin, tetracyclines, or phototherapy. In unrelenting cases, topical tacrolimus or low-dose methotrexate may be utilized.2 The patient in this case healed without intervention or complication within a month.
Amanda Stallings is a fourth-year medical student at Kansas City University and Dominique Jacobs is a fourth-year medical student at Philadelphia College of Osteopathic Medicine.
1. Alexander S, Ralph R. PLEVA: a scary but benign rash. Visual J Emerg Med. 2021;25. doi:10.1016/j.visj.2021.101097
2. Habif TP. Clinical Dermatology: a Color Guide to Diagnosis and Therapy, 6th ed. Elsevier; 2015.
3. James W, Berger T, Elston D. Andrew’s Diseases of the Skin, 12th ed. Elsevier; 2016.
4. Moy A, Sun J, Ma S, Seminario-Vidal L. Lymphomatoid papulosis and other lymphoma-like diseases. Dermatol Clin. 2019;37(4):471-482. doi:10.1016/j.det.2019.05.005
5. Taylor S, Kelly PA, Lim H, Serrano AM. Taylor and Kelly’s Dermatology for Skin of Color 2/E, 2nd ed. McGraw-Hill Education/Medical; 2016.