SARCOID - pediagenosis
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Wednesday, September 23, 2020

SARCOID

SARCOID

Sarcoid, or sarcoidosis, is a relatively common condition that can affect many organ systems. There is a wide spectrum of disease activity, from localized skin disease to widespread involvement of the integumentary, pulmonary, cardiac, renal, gastrointestinal, ophthalmic, endocrine, neurological, and lymphatic systems. However, most cases are mild in nature and can be controlled with proper care. Although an infectious etiology has often been theorized, no conclusive evidence has been established. This idiopathic condition can produce multiple skin findings. The skin findings should cause the attending physician to look for systemic involvement.

CUTANEOUS MANIFESTATIONS OF SARCOID
CUTANEOUS MANIFESTATIONS OF SARCOID

Clinical Findings: Sarcoidosis can occur in any ethnic population, but it is seen at a higher rate in African Americans. It also has a higher incidence in women. The usual age at onset is before 40 years. Up to 90% of patients with sarcoid have a benign clinical course with no increased mortality. Sarcoidosis has been reported to occur in a familial form, which has led researchers to look for specific genetic defects that could explain the disease. However, sarcoid remains an idiopathic multisystem disease. There are many distinct clinical expressions of the disease that are common enough that they have been named, including Löfgren’s syndrome, lupus pernio, Darier-Roussy sarcoid, Heerfordt syndrome, and Mikulicz syndrome.

Sarcoid can affect the skin in a multitude of ways. There are both specific and nonspecific skin findings. The most common nonspecific skin finding is erythema nodosum. Erythema nodosum affects the lower anterior extremities. It manifests as tender subcutaneous nodules or plaques. Examination of biopsy specimens shows a nonspecific form of panniculitis. The etiology of erythema nodosum in patients with sarcoid is poorly understood.

The lesions of sarcoid that occur within the integumentary system are quite varied. The most common specific skin lesion is a slightly brownish to red-brown papule, plaque, or nodule with varying amounts of hyperpigmentation. Sarcoid is a mimicker of many other conditions, especially in its skin lesions. Macular lesions, ulcerations, subcutaneous nodules, annular plaques, ichthyosiform erythroderma, and alopecia have all been described as potential presentations of sarcoid.

The extracutaneous organ system most commonly involved is the pulmonary system. There is a relatively straightforward classification that describes the stages of pulmonary sarcoid based on radiographic findings. The higher the radiographic stage, the more severe the disease. Isolated bilateral hilar adenopathy is the most common pulmonary finding, and it is the basis for stage I radiographic disease. These patients are most commonly asymptomatic, and the adenopathy is found on routine radiographic testing. Any findings of pulmonary sarcoid should prompt referral of the affected individual to a pulmonologist for pulmonary function testing.

Löfgren’s syndrome is defined by the acute onset of erythema nodosum, almost exclusively in young adult women; it is seen in association with fever, bilateral hilar adenopathy, and uveitis. Other, non-specific constitutional signs are often present. The erythrocyte sedimentation rate is uniformly elevated. For some unknown reason, this syndrome is most commonly seen in young Caucasian women. This form of sarcoidosis typically resolves spontaneously within 2 to 3 years.

Lupus pernio is the name given to the clinical findings of specific cutaneous sarcoid involvement of the nose and the rest of the face. This form of sarcoid is quite resistant to therapy, runs a more prolonged course, and is often difficult to treat. The skin findings are typically shiny brown-red plaques, papules, and nodules overlying the nose and other regions of the face. The involvement can become so severe as to cause disfigurement of the nose by shiny red-brown papules and plaques. Lupus pernio has nothing to do with the autoimmune disease lupus. Lupus pernio can be very difficult to treat, and systemic immune suppression is often required.

Subcutaneous sarcoidosis, also called Darier-Roussy sarcoid, is an uncommon condition that manifests as subcutaneous plaques of varying size. This is a rare finding in patients with sarcoid. It manifests as slightly tender, dermal nodules with an overlying hyperpigmentation or normal-appearing skin. A biopsy specimen taken from one of the subcutaneous nodules shows the typical findings of sarcoid.

Heerfordt syndrome is an extremely rare version of sarcoidosis that manifests more commonly in young adult men than in women. It is manifested by fever, parotid gland hypertrophy, and lacrimal gland enlargement in association with facial nerve palsy and uveitis. Neurological involvement with sarcoidosis may cause papilledema and cerebrospinal fluid pleocytosis, indicating an inflammatory reaction pattern. Meningism can occur with headache, spinal stiffness, and photophobia. Mikulicz syndrome is not specific to sarcoid. It is manifested by bilateral enlargement of various glands, including the parotid, submandibular, and lacrimal glands. The tonsillar tissue may also be involved. Fever is common, as is the subsequent development of dry eyes and mouth due to the widespread, often painless, inflammation of the affected glands. It has been seen with uveitis and is considered by some as a variant of Sjögren’s syndrome.

Diagnostic testing to confirm sarcoid includes, most importantly, a tissue biopsy. Tissue sampling is diagnostic and should lead the physician to search for other organ systems involved with sarcoidosis. Laboratory testing may show elevated levels of serum calcium and angiotensin-converting enzyme. Chest radiographs can identify a spectrum of disease that is staged by certain criteria. Patients uniquely show a decreased ability to mount a delayed-type hypersensitivity reaction. This may be manifested by an inability to react to intradermally placed antigens such as tuberculin or candida and is termed anergy. Sarcoid patients in the past were frequently found to have a positive Kveim test. This test is no longer clinically performed because of the danger of transmitting a bloodborne pathogen. The test was performed by interdermal placement of a small amount of a suspension of human spleen and lymph node that had been affected by sarcoid, similar to the placement of a purified protein derivative (PPD) test for tuberculosis. This test was found to be positive in more than 85% of patients with sarcoid.

Mortality is uncommon but may occur secondary to severe cardiac, renal, or pulmonary involvement.

SYSTEMIC MANIFESTATIONS OF SARCOID
SYSTEMIC MANIFESTATIONS OF SARCOID

Pathogenesis: The exact etiology of sarcoidosis is unknown. For years, scientists have been looking at the potential causative link between sarcoid and an infectious agent, usually an atypical mycobacterial agent. However, no conclusive evidence has been reported to indicate that sarcoid is caused by an infectious disease. Histology: The classic finding of multiple, noncaseating epithelioid granulomas with a sparse surrounding inflammatory infiltrate is the hallmark of sarcoidosis.

The granulomatous findings are consistent across all of the various tissues affected by sarcoid. Many nonspecific histological findings can also be seen, but not on a consistent basis; these include Schaumann bodies and asteroid bodies.

Treatment: The treatment for sarcoid has been consistent over time and includes nonspecific immunosuppression, most commonly with oral corticosteroids such as prednisone. Isolated cutaneous findings may be treated with topical corticosteroids or intralesional steroid injections. Methotrexate is a steroid-sparing agent that is used for difficult-to-control disease and for lupus pernio. The anti tumor necrosis factor medications, infliximab and adalimumab, have been used with some success. The use of hydroxychloroquine has also been advocated for treatment of cutaneous sarcoid.


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