Treatment of cutaneous sarcoidosis
What is sarcoidosis?
It is an inflammatory disease that mainly affects the lymph nodes , lungs and skin. The inflammation of the tissues caused by sarcoidosis is secondary to the formation of the so-called naked noncaseating granulomas, which are accumulations of activated macrophages, and whose presence is the histological data that defines this disease.
Macrophages are part of our immune system and have the mission of phagocytosing (“eating and digesting”) cellular debris among other particles.
Why does sarcoidosis appear?
Granulomatous inflammatory diseases are thought to appear in response to the presentation of an unknown foreign antigen that causes an attempt to reject and eliminate it through the formation of granulomas, whose mission is to degrade its remains.
Sarcoidosis is a disease of unknown cause, although there is a genetic predisposition and several environmental etiological agents (probably infectious) have been implicated based on the preference that this pathology has to appear in certain geographical areas, races (African Americans and Scandinavians are at greater risk), times of the year (April – June) and occupations (outbreaks have been described in health personnel, aircraft pilots, firefighters and office workers).
What external factors have been implicated in the origin of sarcoidosis?
Although no clear cause of this disease has been found, it seems that some microorganisms are capable of inducing an inflammatory response practically the same as sarcoidosis, such as some mycobacteria, fungi and parasites.
Likewise, other environmental substances such as pine pollen , talc, aluminum, beryllium and zirconium have been implicated in the origin of sarcoidosis.
What organs can sarcoidosis affect?
Granulomas form occurs primarily, but not constantly, in the intrathoracic lymph nodes , lungs, skin , and eyes. More rarely, they can occur in the bones, nervous system, or kidneys.
What type of involvement does cutaneous sarcoidosis cause?
Sarcoidosis can manifest itself on the skin in a specific or non-specific way. Specific lesions are secondary to the formation of naked non-caseating granulomas on the skin and their histological study – biopsy – allows the diagnosis of sarcoidosis. A classic characteristic of specific lesions is the orange coloration “apple jelly” that they acquire when pressed with a transparent crystal (diascopy), typical of granulomatous disorders.
Specific lesions of cutaneous sarcoidosis are:
· Sarcoid maculo-papules.
· Sarcoid plates.
· Lupus pernium.
· Scarring sarcoidosis.
· Subcutaneous sarcoidosis.
Nonspecific lesions are more frequent in systemic sarcoidosis and are a cutaneous inflammatory response to the presence of this or another internal disease. Biopsy or the presence of these nonspecific lesions does not allow the diagnosis of sarcoidosis, as they are not exclusive to this disorder. The most common nonspecific lesion is erythema nodosum and, much more rarely, calcifications, prurigo and erythema multiforme.
Are skin lesions specific to cutaneous sarcoidosis very common?
They occur in 9 – 37% of patients with cutaneous sarcoidosis and, although they can flare up at any time during the course of the disease, they are more frequent at the onset of the disease and it is not uncommon for the disorder to be diagnosed first by the dermatologist. If specific skin lesions of sarcoidosis are suspected, a skin biopsy should be carried out to confirm the diagnosis of the disease.
Do specific skin lesions have any prognostic significance?
No. The presence or absence of sarcoidosis-specific skin lesions is not related to the course of systemic disease. However, some types of lesions are more commonly associated with some more aggressive forms of sarcoidosis.
What type of specific skin lesions are there in sarcoidosis?
There are different types of injuries, which can be grouped into these categories:
· Macular-papules. They are the most common form of specific lesion. These are macules (spots) or palpable lesions of less than 1 cm (papules) of erythematous-purplish-brown color that appear on the face – especially around the eyes and in the nasolabial folds – and on the extremities. Sarchoid maculo-papules are usually associated with acute forms of sarcoidosis (acute uveitis, hilar or peripheral lymphadenopathy and granulomatous infiltration of the parotid gland). It is not uncommon for sarcoid maculo-papules to disappear spontaneously in a course of less than two years.
· Plaques. They are almost as common as maculo-papules and manifest as rounded or oval plaques, indurated to the touch, and erythematous-brownish in color. Their course is usually slower than that of maculo-papules. There is a variant with annular plaques, which is more common on the face and neck. Sarchoid plaques are usually associated with chronic forms of sarcoidosis, with persistent hilar adenopathies, pulmonary infiltrates, pulmonary fibrosis, splenomegaly, or chronic uveitis.
· Lupus pernio. It is the most characteristic skin lesion of sarcoidosis. It is usually typical of older patients, of the female gender and with long-standing forms of sarcoidosis. It consists of violet, indurated, painless plaques and nodules located on the nose, cheeks, ears, lips and forehead. Lupus pernio is usually associated with sarcoid involvement with pulmonary fibrosis, chronic uveitis and bone cysts. In cases of lupus pernio nasal, it is common for the patient to suffer from involvement of the upper respiratory tract (nasal mucosa, pharynx and/or larynx).
· Scarring sarcoidosis. This is the specific infiltration by granulomas of old scars (interventions, vaccinations, tattoos, acne…), which become erythematous-purplish and indurated to the touch. It is a very characteristic sign of sarcoidosis and is proportionally related to the activity of the disease, as it usually occurs in acute phases of the disorder.
· Subcutaneous sarcoidosis. It is a rare form. Most cases occur in women between the fifth and sixth decades of life. It consists of mobile, painless nodules , indurated to the touch and the same color as normal skin. They are usually located on the extremities, especially on the forearms.
What are the non-specific skin lesions of sarcoidosis?
These are cutaneous manifestations that can accompany sarcoidosis and other diseases. The most common form is erythema nodosum, which consists of the appearance of subcutaneous plaques and erythematous and painful nodules . It is not uncommon for it to be the first manifestation of the disease and usually indicates an acute and benign presentation of the disease. It is typical of young patients and can occur in up to 40% of patients with sarcoidosis. If erythema nodosum is accompanied by a presentation with fever and hilar and paratracheal lymphadenopathy, the joint picture is called Löfgren’s syndrome (which may also be associated with uveitis and arthralgias).
Other nonspecific lesions much less common in sarcoidosis include calcifications, prurigo, erythema multiforme, and neutrophilic forms of dermatosis.
My dermatologist has diagnosed me with skin sarcoidosis. What’s the next step?
After the diagnosis of cutaneous sarcoidosis, if the disease has appeared only with skin lesions, it is advisable to carry out an extension diagnosis to assess which organs may be affected by the disease. It is common for the dermatologist to order a thoracic imaging study (usually an X-ray), a fundus to assess if there are lesions in the eye, a 24-hour urine test to observe some associated alterations (hypercalciuria – excess elimination of calcium in the urine) or other tests that the patient considers appropriate if the patient reports any symptoms.
How is cutaneous sarcoidosis treated?
The treatment of choice for cutaneous sarcoidosis with systemic involvement is the use of oral corticosteroids, with doses of prednisone varying between 0.5 – 1 g/kg weight/day depending on the organs involved. In isolated skin lesions, it is possible to use potent topical and/or intralesional corticosteroids.
Other therapeutic options to be evaluated in each case are different drugs with anti-inflammatory and/or immunomodulatory action, such as antimalarials, allopurinol, thalidomide, minocycline, methotrexate, mycophenolate or infliximab.
REFERENCES
· Yolanda Fortuño, Isabel Gallego, Joaquim Marcoval. Cutaneous sarcoidosis. Actas Dermosifiliogr. 2004;95:137-53.