What is the diagnosis and treatment for guttate psoriasis?

From the Guidelines

Guttate psoriasis should be treated with narrow-band UVB phototherapy, which has been shown to be more effective than broadband UVB in achieving clearance and inducing remission, with a remission rate of 38% after 1 year, as compared to 5% with broadband UVB 1. The treatment of guttate psoriasis typically begins with topical corticosteroids, but for more widespread cases, narrow-band UVB phototherapy is a highly effective option.

• The initial dosing for narrow-band UVB phototherapy should be according to skin type (130-400 mJ/cm2) or the minimum erythema dose (MED) (50% of MED), with subsequent dosage increases by 15-65 mJ/cm2 or 10% of the initial MED, and treatment should be administered 3-5 times a week 1.
• The response to narrow-band UVB phototherapy is often observed within 8-10 treatments, and a single course typically consists of 15-20 treatments, with the possibility of maintenance therapy to prolong remission 1.
• It is essential to note that narrow-band UVB phototherapy has a more favorable long-term outcome compared to broadband UVB, with a higher remission rate and potentially fewer side effects 1.
• In cases where phototherapy is not suitable or effective, systemic medications such as methotrexate or biologics may be considered, with methotrexate being a viable option for severe cases, starting at a dose of 7.5mg weekly, and with proper monitoring for potential side effects such as hepatic toxicity and bone marrow suppression 1.
• The pathophysiology of guttate psoriasis involves T-cell activation and inflammatory cytokine release following an immune response, typically to streptococcal antigens, leading to accelerated skin cell turnover and the characteristic lesions.
• Avoiding triggers like stress, skin injury, and certain medications can help prevent flares, and moisturizers should be applied regularly to maintain skin hydration.
• It is crucial to weigh the benefits and risks of each treatment option and to consider the individual patient's circumstances and medical history when making a treatment decision.

From the Research

Definition and Characteristics of Guttate Psoriasis

• Guttate psoriasis is a variant of psoriasis characterized by scattered "drop-like" papules and plaques, accounting for up to a quarter of psoriasis cases 2.
• It commonly arises 3-4 weeks following a beta hemolytic streptococcal infection 3.
• The disease may be triggered by a streptococcal infection, and penicillin should be applied in addition to local corticosteroids with UVB in the treatment of guttate psoriasis 4.

Treatment Options for Guttate Psoriasis

• The mainstay treatment includes photo therapy and topical steroids 3.
• Topical corticosteroids and calcipotriol creams had the most evidence for efficacy 2.
• Phototherapy had the most robust evidence, with narrowband ultraviolet B (UVB) being the most effective 2.
• Systemic therapies, including traditional immunosuppressants, antibiotics, retinoids, and biologics, can be used as second-line or third-line treatment 2.

Recommendations for Treatment

• A treatment algorithm is proposed, with topical corticosteroids and calcipotriol cream, in combination with phototherapy, as first-line therapy 2.
• Antibiotics can be used as supportive therapy if applicable 2.
• Methotrexate or cyclosporine can be used as second-line therapy, and biologics can be used as third-line treatment for severe and refractory cases 2.
• Topical treatments combining corticosteroids and vitamin D analogues are well-established first-line treatments in mild-to-moderate psoriasis 5.

Importance of Accurate Diagnosis and Treatment

• Guttate psoriasis may be misdiagnosed as an allergy to antibiotics, which can delay and make treatment more difficult 3.
• Accurate diagnosis and treatment are crucial to prevent progression to chronic plaque psoriasis, which can occur in up to 39% of cases 2.