Other Viral Exanthems
Papular Purpuric Glove & Socks Syndrome & Parvovirus-induced Petechial Syndromes
Papular purpuric glove and socks syndrome (PPGSS) is a distinctive exanthem, which is usually caused by parovovirus B19. While other viruses, such as CMV, EBV, measles and HHV-6, have also been considered as causative agents for PPGSS, most studies employing seroconversion, viral DNA detection and immunohistochemistry still strongly support parvovirus B19 as the main etiologic agent of PPGSS.
In 1990, Harms et al. first described PPGSS. Clinically, it is characterized by symmetric, painful erythema, and edema of the hands and feet that later progresses to a petechial rash. Edema and erythema can be observed on the buccal and genital mucosa, and on the inner aspect of the thighs (Figure 7). Unlike EI, patients with PPGSS are contagious when they exhibit the exanthem.
Petechiae coalescing into purpura over the upper thighs.
Other distinctive localized forms of parvovirus-related petechiae and purpura have been described, and given names such as 'bathing suit' and 'acropetechial' syndrome.[60,62,63] Parvovirus B19 has been described recently to cause generalized petechiae.[64–66] The differential diagnosis includes allergic contact dermatitis, rickettsial infections and Kawasaki disease. Treatment is symptomatic, and diagnosis can be made clinically or serologically.
Pityriasis rosea is an acute self-limiting and distinctive exanthem, characterized by oval erythematous-squamous lesions of the trunk and limbs, which usually spares the face, scalp, palms and soles. It is thought to be virally induced because of features such as an associated prodromal symptoms and seasonal clustering of cases. Pityriasis rosea derives its name from pityriasis meaning bran-like, and rosea meaning pink. It has been linked to HHV-6 and HHV-7,[67–69] but this association has been disputed.[70,71]
Classically, pityriasis rosea begins as an erythematous, scaly patch on the trunk, known as a herald patch. This large lesion is commonly 2–10 cm in diameter, ovoid, erythematous and slightly raised, with a typical collarette of scale at the margin. At times, the herald patch may be absent or overlooked. In one series, only 17% of patients referred to a dermatology clinic reported a herald patch. Days to weeks later, numerous smaller scaly papulosquamous plaques develop on the trunk along the lines of skin cleavage with a collarette of scale (Figure 8). The plaques usually spare the face, scalp and distal extremities.
Pink papulosquamous plaques with a collarette of scale over the trunk.
In children, pityriasis rosea may affect the face and extremities other than the trunk, and this is referred to as inverse pityriasis rosea. In particular, dark-skinned children seem to have more frequent facial and scalp involvement. In addition, vesicular, pustular, urticarial and hemorrhagic variants have also been described. The differential diagnosis includes tinea corporis, guttate psoriasis, pityriasis lichenoides and syphilis.
The rash of pityriasis rosea typically lasts approximately 5 weeks, and resolves by 8 weeks in more than 80% of patients. Clearance usually occurs within 6 weeks, and lesions may fade with residual hypopigmetation. Diagnosing pityriasis rosea is nearly always made by history and physical examination alone. In certain atypical cases, a skin biopsy may prove useful in differentiating pityriasis rosea from other exanthems.
Although some studies have shown improvement with systemic erythromycin and systemic ACV,[74,75] treatment is generally supportive. There is some evidence for narrow-band ultraviolet-B phototherapy.[76,77] Topical steroids may be used for associated pruritus.
Erythema multiforme (EM) is a relatively uncommon disorder, characterized by the abrupt onset of multiple target skin lesions. It is frequently recurrent, and some individuals have monthly episodes. HSV appears to be responsible for precipitating most cases of EM episodes in children.[79,80] Other infectious agents and medication have also been implicated. The EM skin lesions characteristically occur 1–10 days after an episode of herpes labialis or genitalis, and appear as 'target' lesions, characterized by a central dusky zone surrounded by an inner ring of pale edema, and an outer ring of erythema. The central area may also be vesicular. The eruption is symmetric and is often seen over the hands and feet. The individual lesions may remain fixed for approximately 1 week, and the entire episode may last for 2–3 weeks. The differential diagnosis includes annular urticaria, acute hemorrhagic edema of infancy, urticarial vasculitis and Stevens–Johnson syndrome. The diagnosis can usually be made clinically, and patients are treated symptomatically. Childhood HSV-associated EM may be unresponsive to treatment with oral steroids or oral or topical ACV. Frequent recurrences of EM may be treated with prophylactic ACV.
Unilateral Laterothoracic Exanthem
Unilateral laterothoracic exanthem (ULTE) is an eruption that begins unilaterally in the axillae or groin, and spreads centrifugally (Figure 9). It has a prolonged course and usually resolves within 4–6 weeks. ULTE was first described as a new clinical entity by Bodemer and de Prost in 1992, but, in the past has been described under different names from as early as 1962.[84,85] In the literature, ULTE has other designations, such as asymmetric periflexural exanthem and unilateral mediothoracic exanthem.[86,87]
Erythematous papules over the left axillae and upper left trunk.
Clinically, ULTE is usually preceded by an upper respiratory or gastrointestinal prodrome, and is characterized by a unilateral and localized exanthem, often in the axillary region (Figure 9), which spreads in a centrifugal pattern, sometimes reaching the contralateral side. The mucous membranes, face, palms and soles are generally spared.
The etiology is unknown, but the frequent early age of onset, the seasonal pattern, the associated prodrome, the lack of response to systemic antibiotics and the possibility of familial cases suggest an infectious cause. Infectious agents linked with the eruption of ULTE include parainfluenza 2 and 3, adenovirus, parvovirus B19, and HHV-6 and -7. Recently, primary EBV infection has been linked with ULTE.[90,91] ULTE probably represents a distinct cutaneous reaction to several infectious agents.
The eruption usually lasts 4–6 weeks, although some cases can persist for more than 8 weeks.[88,92] The differential diagnosis includes pityriasis rosea, papular acrodermatitis of childhood and allergic contact dermatitis. The diagnosis is made clinically and treatment is supportive.
Nonspecific Viral Exanthem
A number of viruses can cause an exanthem associated with an upper respiratory or gastrointestinal infection. These include the nonpolio enteroviruses in the summer months, and rhinovirus, adenovirus, parainfluenza virus, respiratory syncytial virus and influenza virus in the winter. The exanthem usually consists of erythematous macules and papules, but may be urticarial.[94,95]
Pediatr Health. 2010;4(6):623-635. © 2010 Future Medicine Ltd.
Cite this: Characterizing Viral Exanthems - Medscape - Dec 01, 2010.