Sarcoidosis is a multisystem granulomatous disorder of unknown etiology that can involve all organ systems to varying extent and degree.

• Sarcoidosis commonly involves patients between 20 and 60 years of age^[1]. Lung is the most common organ involved by sarcoidosis, but up to 30% of patients present with extrapulmonary sarcoidosis^[2][3]. Pulmonary sarcoidosis commonly presents with cough, dyspnea, chest pain, and infrequently fatigue, malaise, fever, and weight loss^[4].
• Young children can present with skin rash, arthritis, uveitis, and erythema nodosum, without a predominant lung involvement^[5][6]

In 25% of the patients diagnosed with sarcoidosis, cutaneous involvement is seen^[7]. The most common patterns of involvement is: papular, nodular, plaque-like, lupus pernio, erythema nodosum, subcutaneous sarcoidosis. See cutaneous manifestations of sarcoidosis in physical exam for more detail.

In 25% of the patients diagnosed with sarcoidosis, ocular involvement is seen^[8]. Sarcoidosis involves the orbit, anterior segment, posterior segment, conjunctiva, lacrimal glands, and extraocular muscles. the usual symptoms include dry eye, blurred vision, photophobia, red eye, and pain^[9][10] .

• Intraocular sarcoidosis: these include anterior, intermediate, and posterior uveitis. Typical symptoms of anterior uveitis are pain and redness perticularly at the junction between cornea and sclera (limbus), while posterior and/or intermediate uveitis causes no symptom or floaters^[9].
• extraocular orbital sarcoidosis: involvement of lacrimal glands, conjunctiva, extraocular muscles, optic nerve and palpable mass^[11].

Sarcoidosis can involve the larynx, pharynx, nares, and sinuses. The symptoms can include cough, dysphagia, hoarsness, nasal obstruction, nasal crusting, anosmia, epistaxis, and nasal polyposis^[12][13].

The exact rate of myocardial involvement in sarcoidosis is not clear, but it ranges from 5% in patients with systemic sarcoidosis to 25 and even 70% in autopsy studies. Patients may complain of palpitations, syncope, lightheadedness, and chest pain. sudden cardiac death (SCD) can occur^[14][15].

Sarcoidosis can involve both Central and Peripheral nervous system in 5% of patients. The common symptoms include:

• Peripheral facial nerve palsy in 25 to 50% of patients with neurosarcoidosis^[16][17]
• Polyuria and impairment in sleep, thirst, body temprature and libido due to hypothalamic inflammation^[17][18]
• Seizures^[19]

Involvement of the lymph nodes, liver, and spleen is common in sarcoidosis. The patients may present with neck or axillary mass. liver and spleen involvement is usually asymptomatic^[20].

There are 3 common patterns of musculocutaneous involvement in sarcoidosis: 1. Acute sarcoid arthritis or acute polyarthritis 2. Chronic arthritis 3. Myopathy(diffuse granulomatous myositis)^[21].

The presence of erythema nodosum, hilar lymphadenopathy, migratory polyarthralgia, and fever has a 95% diagnostic specifity for sarcoidosis, allowing a diagnosis to be made without biopsy, and is associated with a good prognosis^[22].

In 5% of the patients diagnosed with sarcoidosis, painless swelling of salivary glands and parotid gland occurs. Sicca syndrome and xerostomia may also be seen^[23].

• Symptoms caused by hypercalcemia (presenting feature in 10 to 20 percent of patients)
• Renal colic caused by nephrolithiasis (presenting feature 4 percent of patients)
• Symptoms caused by uremia due to interstitial nephritis
• Symptoms caused by proteinuria (various types of glumerulonephritis may be seen)^[24][25].