A 13-year-old girl with sore throat and diffuse, scaly papules

Issue: December 2013

ByCarrie C. Coughlin, MD

ByMarissa J. Perman, MD

A 13-year-old girl presents to your office with an asymptomatic eruption for 3 days. Her parents report the rash appeared suddenly and involves her scalp, face, trunk and extremities. She denies improvement with application of calamine lotion. No one at home has a similar rash. Upon review of systems, she said she had a sore throat about a week before the eruption, along with a brief period of tactile temperatures.

Physical examination reveals the presence of round and oval, scaly, erythematous papules measuring 3 mm to 10 mm in size. They are distributed over her entire body with sparing of the face, and diffuse silvery, scaling plaques in the scalp.

Carrie C. Coughlin

Marissa Perman

Can you spot the rash?

Diagnosis: Guttate psoriasis

Psoriasis has several different morphologies, including plaque, guttate, inverse (present in body folds or creases), pustular, infantile and nail-predominant forms. Guttate psoriasis can present without any apparent trigger, or can follow streptococcal infections (both pharyngeal and perianal). In this case, the patient has guttate psoriasis induced by streptococcal pharyngitis.

Streptococcal infections can trigger guttate psoriasis via T lymphocyte activation. These lymphocytes can be activated by streptococcal superantigens binding directly to major histocompatibility complex (MHC) class II molecules (skipping the intracellular processing typically required by antigens) and then binding CD4+ T lymphocytes. In addition, the streptococcal M protein can stimulate T lymphocytes in psoriatic patients, thus promoting the cytokine response. Psoriasis is classically a T helper 1 (Th1) mediated dermatosis. Thus, the production of interleukin-2, gamma interferon, tumor necrosis factor alpha, and interleukin-6 is upregulated in patients with psoriasis.

Guttate psoriasis may resolve within weeks to months with dyspigmentation that improves with time. However, in many cases, it is persistent or may evolve into chronic plaque psoriasis.

Left figure: Close-up of erythematous, scaly papules on the arm, consistent with guttate psoriasis. Right figure: Erythematous, scaly papules scattered on the arm and an erythematous, scaly plaque, demonstrating both guttate and plaque psoriasis morphologies in the same patient.

Images courtesy of Perman MJ

In one epidemiological study of children with plaque psoriasis, guttate psoriasis was the initial morphology in 29.8% of patients (54 of 181). Half of the patients in this study reported a preceding streptococcal infection. There was no significant difference in the sex or age of the patients with chronic plaque psoriasis that initially presented with a guttate morphology.

The differential diagnosis includes pityriasis rosea, pityriasis lichenoides, secondary syphilis and eczema. The abrupt onset and classic morphology point to guttate psoriasis. Preceding sore throat or red perianal skin can give clues to the diagnosis as well. There is no herald patch or Christmas tree pattern (as in pityriasis rosea) and the course does not typically wax and wane, as in pityriasis lichenoides chronica. If there is suspicion for syphilis, serological testing should be performed. Some patients may experience pruritus, but itch is not a predominant feature as compared with patients with eczema.

The mainstay of treatment is topical corticosteroids. However, if a patient has an active streptococcal infection, this should be treated with the appropriate antibiotic first because a few patients may clear with antibiotic therapy alone. Mid-strength topical corticosteroids are generally appropriate for use on the body, with low-strength corticosteroids or topical calcineurin inhibitors (off-label) used on the face, body folds or genitalia. Guttate psoriasis may be widespread, making topical therapies too labor intensive. In those cases, patients may benefit from ultraviolet therapy. If patients go on to develop chronic plaque psoriasis, treatment may be adjusted as needed. For the cohort of patients who will eventually clear completely, topical therapies should be tapered as they improve. Some patients may have a recurrence of guttate psoriasis with subsequent streptococcal infections.

Physicians should be aware of patients, particularly children, presenting with the guttate form of psoriasis and the association with streptococcal infection.

References:

Bhutani T. Pediatr Ann. 2012;41:e1-7.
Hogan PA, Langley RGB. Papulosquamous diseases: Psoriasis vulgaris. In: Schachner LA, Hansen RC, eds. Pediatric Dermatology. Elsevier;2011:901-914.
Mercy K. Pediatr Dermatol. 2013;30:424-428.

For more information:

Carrie C. Coughlin, MD, is a resident in the Division of Dermatology, Washington University School of Medicine, St. Louis. She can be reached at ccoughli@dom.wustl.edu.
Marissa J. Perman, MD, is an attending physician at The Children’s Hospital of Philadelphia. She can be reached at permanm@email.chop.edu.

Disclosure: Coughlin and Perman report no relevant financial disclosures.