It's the early morning hours at the end of a night shift and you get a call from the triage nurse about a patient who just checked in. The patient is an otherwise healthy young female who complains of a new rash over her chest and abdomen. She states that she has had several days of sore throat and then developed the rash overnight.
The patient is afebrile and has otherwise normal vital signs.
The triage nurse wants to know if the patient needs to be isolated.
What would be your answer? What is your differential diagnosis and how would you treat this patient?
Scroll down for Case Conclusion.
Final Diagnosis: Acute guttate psoriasis
Case Conclusion: The patient was noted to have numerous papules and one larger plaque covered in a silvery scale. Coupled with the history of sore throat suggesting possible Strep pharyngitis, Dermatology made the diagnosis of classic guttate psoriasis and recommended treatment with topical steroids.
Learning points: The differential diagnosis for the well-appearing patient with a scaly, diffuse rash is relatively broad. Some causes are overtly infectious (tinea corporis, secondary syphilis) while some are likely immune-mediated responses to a previous viral or bacterial infection (Pityriasis, guttate psoriasis) . Diagnosis is made based on clinical appearance, history and in some cases skin scrapings (tinia), biopsy (psoriasis), or serologic testing (syphilis).
Psoriasis is a common skin disorder. In most adult patients, chronic plaque type psoriasis is the most common form. There are several clinical variants of psoriasis that have a distinct appearance and may not be immediately recognized as psoriasis . These include:
- Generalized pustular psoriasis which can be triggered by irritating topical therapy or abrupt steroid withdrawal
- Erythrodermic psoriasis which can involve up to 90% of the skin surface is an inflammatory phase marking the transition to more extensive involvement.
- Guttate psoriasis which is more common in young adults and associated with streptococcal pharyngitis.
Like rheumatic fever, glomerulonephritis, toxic shock syndrome, PANDAS and erythema nodosum, guttate psoriasis is a nonsuppurative complication of Streptococcus pyogenes (Group A Strep) infection [2,3,4]. It is specifically associated with acute pharyngitis and 20-97% of patients with acute guttate psoriasis will be culture-positive for S.pyogenes . Patients with a family history of psoriasis are at higher risk. It is usually self-limited, although approximately one third of patients will develop chronic psoriasis following a single episode . It is thought that guttate psoriasis is mediated by a secreted streptococcal superantigen (pyrogenic exotoxin C) that causes proliferation and accumulation of Vß2+T-cells in psoriatic lesions. In turn, these T-cells secrete growth factors that induce keratinocyte proliferation .
Despite the association with streptococcal infection, there is no convincing evidence that antibiotic therapy has a role in the management of guttate psoriasis. In the only blinded randomized control trial of antibiotics vs. placebo, 43 patients with guttate psoriasis who had culture or serologic evidence of Group A strep infection were randomized to receive no treatment, oral erythromycin or oral penicillin x 14 days. No statistically significant or qualitative improvement was found between groups at 14 days or 6 weeks of follow-up . Current recommendations for treatment of guttate psoriasis are therefore limited to topical steroids or various forms of tar in conjunction with Ultraviolet B phototherapy .
Case Conclusion by Maia Dorsett (@maiadorsett)
- Balato, N., Di Costanzo, L., & Balato, A. (2009). Differential diagnosis of psoriasis. The Journal of Rheumatology, 83, 24-25.
- Whyte, H.J., & Baughman, R.D. (1964). Acute guttate psoriasis and streptococcal infection. Archives of dermatology, 89(3), 350-356.
- Telfer, N. R., Chalmers, R. J., Whale, K., & Colman, G. (1992). The role of streptococcal infection in the initiation of guttate psoriasis. Archives of dermatology, 128(1), 39-42.
- Naldi, L., Peli, L., Parazzini, F., Carrel, C. F., & Psoriasis Study Group of the Italian Group for Epidemiological Research in Dermatology. (2001). Family history of psoriasis, stressful life events, and recent infectious disease are risk factors for a first episode of acute guttate psoriasis: results of a case-control study. Journal of the American Academy of Dermatology, 44(3), 433-438.
- Martin, B. A., Chalmers, R. J., & Telfer, N. R. (1996). How great is the risk of further psoriasis following a single episode of acute guttate psoriasis?. Archives of dermatology, 132(6), 717-718.
- Leung, D. Y., Travers, J. B., Giorno, R., Norris, D. A., Skinner, R., Aelion, J., ... & Kotb, M. (1995). Evidence for a streptococcal superantigen-driven process in acute guttate psoriasis. Journal of Clinical Investigation, 96(5), 2106.
- Dogan, B., Karabudak, O., & Harmanyeri, Y. (2008). Antistreptococcal treatment of guttate psoriasis: a controlled study. International journal of dermatology, 47(9), 950-952.
- Chalmers, R. J. G., O'Sullivan, T., Owen, C. M., & Griffiths, C. E. M. (2001). A systematic review of treatments for guttate psoriasis. British Journal of Dermatology, 145(6), 891-894.