Derm Dx: Rash following a sore throat

The word guttate is derived from the Latin word gutta, meaning drop. As its name suggests, guttate psoriasis clinically presents acutely as small, drop-like, papules with an erythematous base covered by a fine silvery scale. These well-demarcated lesions can range...

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The word guttate is derived from the Latin word gutta, meaning drop. As its name suggests, guttate psoriasis clinically presents acutely as small, drop-like, papules with an erythematous base covered by a fine silvery scale.

These well-demarcated lesions can range from 1 mm to 10 mm in diameter and are primarily found on the trunk and proximal extremities, sparing the palms and soles. Lesions may also be found on the face, ears, scalp and distal extremities.

New lesions typically appear in the first month of the disease, followed by stability of the lesions in the second month; remission commonly begins after 60 days.¹

Guttate psoriasis is often asymptomatic; however, mild pruritis may be reported. Chronic psoriatic signs such as nail pitting and ridging, as well as the “oil-drop” sign, are frequently absent as this is often the patient’s first manifestation of psoriasis.

Guttate psoriasis most commonly occurs in children and young adults aged younger than 30 years and may be seen one to three weeks following a group A β-hemolytic streptococcal (GAS) infection.² A strong association of guttate psoriasis following perianal streptococcal infections in children has also been well established.^3,4

Although the correlation of guttate psoriasis and streptococcal infections is much more common, other organisms such as Staphylococcus aureus, Candida albicans and Malassezia, have been implicated as well.⁵

Tumor necrosis factor-α (TNF-α) inhibitors and other immunomodulating drugs also have a strong association with the presentation of all types of psoriasis, including guttate psoriasis.^6,7,8 Full resolution of the disease usually occurs from 12-16 weeks without treatment.

Patients frequently have no evidence of psoriasis for prolonged periods of time following complete resolution. Although guttate psoriasis is self-limiting and complete resolution is common, it is thought that it may be a precursor to the development of chronic plaque psoriasis in the future.

One study showed that 33% (5 out of 15) patients had chronic psoriasis 10 years following their initial presentation of acute guttate psoriasis.⁹ However, more studies are needed in order to fully establish this hypothesis.

Diagnosis

Given the distinct presentation of acute guttate psoriasis along with the common history of symptoms of a prior streptococcal infection, guttate psoriasis is largely a clinical diagnosis. Biopsy of one of the lesions can confirm psoriasis, but is often not necessary. Throat or perianal cultures can reveal the presence of Streptococcus species and an elevated antistreptolysin O titer can confirm a prior streptococcal infection.

The differential diagnosis of a rash of this type includes nummular dermatitis, tinea corporis, secondary syphilis and pityriasis rosea. Other diagnoses to consider are pityriasis lichenoides, atopic dermatitis, parapsoriasis, viral or drug exanthems and cutaneous T-cell lymphoma, all of which can be differentiated from guttate psoriasis in some way.

The plaques of nummular dermatitis are larger (from 1 cm to 5 cm in diameter), more coin shaped and less numerous. They have a thin, finer scale and are very pruritic.

The lesions of tinea corporis can vary in size, shape and distribution. Tinea corporis has the characteristic advancing raised scaly border and commonly has central clearing. Several lesions can coalesce to cover wide areas of the body.

With secondary syphilis, the patient will frequently have systemic complaints and the lesions do not spare the palms and soles. If syphilis is suspected, then syphilis serology should be conducted.

The lesions and distribution of pityriasis rosea are very similar to guttate psoriasis, however the scale of pityriasis rosea is ring within the border of the plaque, giving it its characteristic “collarette” appearance. Also, the plaques of pityriasis rosea are found along skin lines giving it the classic “Christmas-tree” pattern. A 2 cm to 10 cm round to oval lesion frequently appearing on the trunk, known as a herald patch, often precedes the eruptive phase of pityriasis rosea by a few days to several weeks. As with any dermatologic condition, a meticulous history and thorough physical exam, including all areas of the skin, is necessary for a diagnosis.

Treatment

There is no general consensus on specific treatment guidelines for guttate psoriasis. Many studies have been done with a wide array of treatment plans, all with varying results. There is evidence to support the use of broadband and narrow-band ultraviolet B phototherapy, as well as a psoralen-ultraviolet A (PUVA) radiation treatment for more resistant cases, which has been shown to accelerate the clearance of the lesions.^10,11,12

Topical corticosteroids are commonly prescribed for their anti-inflammatory and vasoconstrictive properties. However, they may be cumbersome to apply if the distribution of lesions is significant. As with other steroid responsive skin disease, care must be taken in prescribing the correct potency for the size and location of the lesions.

Additional studies have shown improvement in the acute episodes of guttate psoriasis with various agents including topical retinoids, tar, surgical tonsillectomy, use of antibiotics and infusions of n-3 fatty acid rich lipid emulsion.^13,14,15,16

However, other studies and literature reviews found no clear benefit to the use of certain antibiotics, or tonsillectomy in the improvement of psoriasis.^17,18,19

Given that the condition resolves spontaneously in a few weeks to months without any treatment, reassurance and emollients may be sufficient.

Erin B. Storie, DO, and Kevin J. Winegar, DO, are Lieutenants in the United States Navy.