Granuloma annulare: Description, Causes and Risk Factors:
A chronic or recurrent, usually self-limited papular eruption that tends to develop on the distal portions of the extremities and over prominences, although the condition may be generalized; waxy papules tend to form annular lesions characterized microscopically by foci of dermal necrosis with mucin deposits, bordered by histiocytes with palisaded nuclei.
Granuloma annulare is a benign skin condition that typically consists of grouped papules in an enlarging annular shape. Their appearance ranges from flesh colored to erythematous. The etiology is unknown, but the disease usually is self-limited. Despite the dramatic appearance of this cutaneous eruption, it generally is asymptomatic; however, there may be some mild pruritus. The eruption can occur anywhere on the body, but it occurs least often on the face and most often on the lateral or dorsal surfaces of the hands and feet.
The cause of this is unknown, but it has been reported to follow trauma, malignancy, viral infections (including human immunodeficiency virus [HIV], Epstein-Barr virus [EBV], and herpes zoster), insect bites, and tuberculosis. A delayed-type hypersensitivity reaction and cell-mediated immune response are hypothesized. In one retrospective study, 12 percent of patients with granuloma annulare had diabetes mellitus. This study did not have a comparison group, so it is not clear whether the prevalence of diabetes mellitus was higher or lower than in the general population. Patients with diabetes mellitus had a higher incidence of chronic relapsing granuloma annulare than patients without diabetes. A case-control study that included patients with and without diabetes failed to reveal any statistically significant correlation between granuloma annulare and type 2 diabetes. Some isolated cases of this found in association with malignant neoplasm have been reported. In these cases, the malignant neoplasms were primarily lymphoma, but some were prostate cancer. Granuloma annulare has occurred in all stages of HIV infection as well.
The frequency of granuloma annulare is in the general population is unknown. Granuloma annulare does not favor a particular race, ethnic group, or geographical area. Localized granuloma annulare is the most common among the various subtypes. Of all patients with granuloma annulare, 9-15% have the generalized variant. Perforating has been reported to have a prevalence of 5% among granuloma annulare subtypes; further, reports suggest that this variant may be more common in the Hawaiian Islands.
Granuloma annulare usually causes no other symptoms, but the rash may be slightly itchy
.Patients usually notice a ring of small, firm bumps (papules) over the backs of the forearms, hands, or feet. Occasionally, they may find a number of rings.Rarely, granuloma
annulare may appear as a firm nodule under the skin of the arms or legs. In some cases, the rash may spread all over the body.
Laboratory studies are largely noncontributory in patients with granuloma annulare (GA). With a classic history and unremarkable physical examination findings (other than the presenting lesion[s]), no additional workup is necessary.If, however, a thorough history is not available or systemic disease is considered likely, appropriate laboratory evaluations should be performed to exclude other diagnostic possibilities.
For example, in subcutaneous it, a CBC count, an erythrocyte sedimentation rate (ESR), and a rheumatoid factor (RF) study may assist in excluding other possible causes for nodules.
Imaging studies are not generally necessary in diagnosing granuloma annulare. However, radiographs, CT scans, or MRIs may be helpful in the evaluation of atypical subcutaneous lesions.
Medical literature contains limited reliable information on the treatment of granuloma annulare. The only double-blind, placebo-controlled crossover study concerning the treatment of disseminated granuloma annulare involved the use of oral potassium iodide. In this series of eight patients, there was no advantage of high-dose potassium iodide over placebo.
Most medical literature on treatment of granuloma annulare is limited to individual case reports and small series of patients treated without a control group. Such studies cannot establish treatment effectiveness, particularly with a self-limited disease.
Because localized granuloma annulare is self-limited and asymptomatic, treatment usually is not necessary. Nevertheless, many patients remain troubled by the appearance and persist in seeking treatment. For patients insisting on treatment, options include intralesional corticosteroid injection with 2.5 to 5.0 mg/mL triamcinolone (Aristocort) into the elevated border, topical corticosteroids under occlusion, cryotherapy, and electrodesiccation. Patients should be warned that all of these treatments could cause scarring and atrophy. One uncontrolled study of 31 patients with localized granuloma annulare showed 81 percent resolution after one treatment with liquid nitrogen or nitrous oxide.
Systemic therapy is required for disseminated granuloma annulare, and many different treatments have been proposed. The possible benefit of treatment, which is unclear given the lack of clinical trials, must be balanced against the significant toxicities of most of these treatments. Therefore, the family physician must proceed with caution and should consider consultation with a dermatologist.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.