An Overview of Guttate Psoriasis

Guttate psoriasis is a form of psoriasis that often appears in the wake of strep throat and other similar infections. Derived from the Latin word gutta (meaning drops), guttate psoriasis is characterized by the spontaneous outbreak of small, pink, teardrop-shaped bumps, usually on the torso, arms, and legs.

You may develop guttate psoriasis only once, or it can recur in tandem with recurrent infections or other possible triggers. It can sometimes be a sign that the more common form of the disease, plaque psoriasis, may eventually develop.

Guttate psoriasis mostly affects children and adults under 30 and accounts for around 10% of all psoriasis cases, according to the National Psoriasis Foundation. It is the second most common form of the disease (next to plaque psoriasis) and, like all forms, can run in families.

Symptoms

Guttate psoriasis has similar features to plaque psoriasis in that it manifests in a sudden flare of erythematous (red) rash covered in scales. But, unlike plaque psoriasis, the rash isn't very thick and tends to be separate rather than clustered.

Guttate psoriasis manifests with the eruption of dozens or even hundreds of small, teardrop-shaped papules (bumps), mainly on the torso or limbs. It can sometimes spread to the face, ears, or scalp, but almost never affects the palms, sole, or nails like other types of psoriasis can.

As the papules begin to heal, they can turn from a light pink to dark red. They rarely leave a scar unless the skin has been scratched excessively.

An episode of guttate psoriasis may last several weeks or months and can affect people previously diagnosed with plaque psoriasis.

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Causes

Guttate psoriasis, like all other types of psoriasis, is a non-contagious autoimmune disease. For reasons not entirely understood, the immune system will suddenly regard skin cells as a threat and launch an inflammatory response to "control" what it presumes to be an infection.

The inflammation, in turn, triggers the hyperproduction of skin cells, causing them to multiply faster than they can be shed. This leads to the appearance of the red, scaly lesions we recognize as psoriasis.

Scientists believe that psoriasis is caused by a combination of genetics and environment. Certain genetic mutations are believed to predispose an individual to psoriasis, but it is only when confronted with specific environmental triggers that symptoms develop.

With guttate psoriasis, scientists have identified a number of mutations—mainly involving the human leukocyte antigen C (HLA-C) group of genes—that are believed to be linked to the disease.

The eruption usually develops two to three weeks after strep infection. Guttate psoriasis can also strike people who recently recovered from tonsillitis, chickenpox, or an upper respiratory tract infection. Because many of these infections are common in childhood, children are disproportionately affected.

Stress, skin trauma, and certain medications (such as beta-blockers and antimalarial drugs) can also trigger the initial or subsequent flare of symptoms. If someone has repeated bouts of guttate psoriasis, they should ​be tested to see if they are a carrier of S. pyogenes.

Diagnosis

There is no cure for psoriasis and no lab tests or imaging studies that can definitively diagnose the disease. The diagnosis is primarily based on a physical examination, a review of your medical history (including a family history of psoriasis), and the exclusions of all other possible causes.

If guttate psoriasis is suspected, your healthcare provider will likely take a blood sample or throat culture to check for strep. If the diagnosis is unclear and there is concern for other conditions a biopsy can be helpful.

If the cause is uncertain, a dermatologist will conduct a differential diagnosis to exclude other diseases with similar symptoms. These may include:

• Cutaneous T-cell lymphoma, a dermatological manifestation of non-Hodgkin lymphoma
• Nummular dermatitis (discoid eczema)
• Pityriasis rosea
• Syphilis
• Tinea corporis (ringworm)

Treatment

Guttate psoriasis tends to be self-limiting and can usually resolve on its own with supportive treatment. The primary goal of treatment is to reduce itchiness that can interfere with sleep and lead to excessive scratching. To this end, treatment may involve:

• Emollient-rich moisturizers
• Topical hydrocortisone cream
• Coal tar lotion
• Dandruff shampoo
• Oral antihistamines
• Cold compresses

In addition, oral antibiotics may be prescribed to treat the underlying strep infection. Options include penicillin, erythromycin, and azithromycin.

Severe cases of guttate psoriasis may require additional treatments. Depending on the percentage of skin involved and/or the frequency of recurrence, treatment options may include:

• Phototherapy (UV light therapy)
• Oral corticosteroids like prednisone
• Topical tazarotene, a retinoid drug that slows the hyperproduction of skin cells
• Apremilast, an anti-inflammatory medication that has been shown to be successful

Disease-modifying antirheumatic drugs (DMARDs) like methotrexate or cyclosporine and biologic drugs like Humira (adalimumab) or Enbrel (etanercept) are generally reserved for cases that eventually become plaque psoriasis. Even then, they are only prescribed when all other conservative options have failed.