Discussion
LCV is a small vessel vasculitis of the dermal capillaries and venules. Histologically, LCV is characterized by fibrinoid necrosis of the vessel wall with frequent neutrophils, nuclear dust, and extravasated erythrocytes.3
Although a thorough evaluation is recommended to determine etiology, about 50% of cases are idiopathic. The most common precipitants are acute infection or a new medication. Postinfectious LCV is most commonly seen after streptococcal upper respiratory tract infection. Among other infectious triggers, Mycobacterium, Staphylococcus aureus, chlamydia, Neisseria, HIV, hepatitis B, hepatitis C, and syphilis are noteworthy. Foods, autoimmune disease, collagen vascular disease, and malignancy are also associated with LCV.4
In our patient we could not find any specific identifiable triggers. However, the presence of a UTI as a precipitating factor cannot be ruled out.5 Moreover, the patient received ciprofloxacin and there have been several case reports of LCV associated with use of a fluroquinolone.6 Nevertheless, in the presence of chronic ITP, which also is an auto-immune condition, an idiopathic cause seemed a reasonable explanation for the patient’s etiopathogenesis.
The cutaneous manifestations of LCV may appear about 1 to 3 weeks after the triggering event if present. The major clinical findings include palpable purpura and/or petechiae that are nonblanching. These findings can easily be confused with other diagnoses especially in the presence of a similar preexisting diagnosis. For example, our patient already had chronic ITP, and in such circumstances, a diagnosis of superimposed LCV can be easily missed without a thorough investigation. Extracutaneous manifestations with LCV are less common. Systemic symptoms may include low-grade fevers, malaise, weight loss, myalgia, and arthralgia. These findings have been noted in about 30% of affected patients, with arthralgia the most common manifestation.7 Our patient also presented with pain involving multiple joints.
The mainstay of diagnosis for LCV is a skin biopsy with direct immunofluorescence. However, a workup for an underlying condition should be considered based on clinical suspicion. If a secondary cause is found, management should target treating the underlying cause, including withdrawal of the offending drug, treatment or control of the underlying infection, malignancy, or connective tissue disease. Most cases of idiopathic cutaneous LCV resolve with supportive measures, including leg elevation, rest, compression stockings, and antihistamines. In resistant cases, a 4- to 6-week tapering dose of corticosteroids and immunosuppressive steroid-sparing agents may be needed.8
Conclusions
Although most cases of LCV are mild and resolve without intervention, many cases go undiagnosed due to a delay in performing a biopsy. However, we should always look for the root cause of a patient’s condition to rule out underlying contributing conditions. Differentiating LCV from any other preexisting condition presenting similarly is important.