What is the recommended treatment for a patient with guttate psoriasis?

Treatment of Guttate Psoriasis

For guttate psoriasis, start with topical corticosteroids (moderately potent, grade III) combined with narrowband UVB phototherapy, screen for streptococcal infection and treat if present, and reserve systemic agents for severe refractory cases. 1

Initial Assessment and Workup

• Screen all patients for streptococcal infection with throat culture or rapid streptococcal antigen test, as guttate psoriasis typically follows streptococcal pharyngitis by 3-4 weeks 1, 2
• Consider anti-streptolysin O (ASO) titers if recent infection is suspected 1
• Recognize that guttate psoriasis is self-limiting in most cases, resolving within 3-4 months without scarring, though 40-50% may progress to chronic plaque psoriasis 3, 4

First-Line Treatment: Topical Therapy

Topical corticosteroids are the most rapid and efficient first-line treatment for mild guttate psoriasis 4:

• Apply moderately potent topical corticosteroids (British National Formulary grade III) as primary therapy 1
• Limit to no more than 100g per month with mandatory regular clinical review 1
• Avoid unsupervised repeat prescriptions 3

Alternative topical agents when corticosteroids alone are insufficient:

• Low concentrations of coal tar (0.5-1.0% crude coal tar in petroleum jelly, increasing as tolerated) - note that erupting guttate psoriasis is commonly less tolerant of topical treatment 3, 1
• Low concentrations of dithranol (0.1-0.25%) in short contact mode (15-45 minutes daily), though great care is needed as guttate lesions are more sensitive 3, 1
• Calcipotriol (vitamin D analogue) can be combined with corticosteroids for enhanced efficacy 4

Second-Line Treatment: Phototherapy

Narrowband UVB phototherapy is especially helpful for moderate-to-severe guttate psoriasis and is more practical than topical therapy when treating numerous widespread lesions 3, 4:

• Administer 3 days per week initially, decreasing to 2 days per week upon improvement 1
• Treatment courses typically last 8-10 weeks 3, 1
• This represents the most robust evidence base among all treatment modalities 5

Antibiotic Therapy Considerations

If active streptococcal infection is documented, treat with phenoxymethylpenicillin or erythromycin 3:

• However, evidence suggests minimal connection between infection resolution and GP lesion remission 5
• For recurrent guttate psoriasis following documented recurrent tonsillitis, refer to otolaryngology for consideration of tonsillectomy 3

Third-Line Treatment: Systemic Therapy

For severe, refractory cases unresponsive to topical therapy and phototherapy 4:

• Methotrexate as second-line systemic option 5, 4
• Cyclosporine as alternative second-line systemic option 5, 4
• Biologics reserved for third-line treatment in severe refractory cases 5, 4
• All systemic agents are absolutely contraindicated in pregnancy and require mandatory contraception counseling 3, 6

Critical Pitfalls to Avoid

• Do not confuse the guttate psoriasis eruption with antibiotic allergy, as the rash typically appears 3-4 weeks after streptococcal infection, which may coincide with antibiotic use 1, 2
• Never use systemic corticosteroids, as they can cause severe disease flare during taper 1
• Avoid high concentrations of tar and dithranol initially, as erupting guttate psoriasis is commonly less tolerant of aggressive topical treatment compared to chronic plaque psoriasis 3
• Do not use commercially available sunbeds (ultraviolet A), as they are rarely effective and may cause premature skin aging 3

When to Refer to Dermatology

• Patients requiring systemic agents should be under continuing supervision of a consultant dermatologist due to potential toxicity 3
• Most patients with stable guttate psoriasis can be managed in primary care with topical agents and phototherapy 3