Sarcoidosis is an inflammatory condition that can impact various organ systems throughout the body. The skin is frequently affected, sometimes serving as the first or even the sole indicator of the disease.
General Appearance of Skin Lesions
Sarcoidosis skin lesions often display a consistent set of characteristics. Their color typically ranges from reddish-brown to purple or violaceous. On individuals with darker skin tones, these lesions might appear more hyperpigmented or purplish, while on lighter skin, they tend to be red or pink. When touched, the lesions can feel firm, waxy, or rubbery. Their surface may be smooth or slightly scaly, and they generally present as rounded or oval shapes, varying in size from small bumps to larger patches.
Specific Manifestations on the Skin
Sarcoidosis can present in several distinct forms on the skin, each with its own visual characteristics. Nodules are larger, deeper lumps that can be painless or slightly tender and commonly develop on the arms.
Papules are small, raised, firm bumps, often less than 1 centimeter in diameter, and can be reddish-brown, violet, tan, brown, or skin-colored. These often appear on the face, particularly around the eyes, or on the neck.
Plaques are raised, flat-topped patches that can be oval or irregular in shape. Their color varies, often appearing reddish-brown, purple, or brown, and they may have a smooth or scaly texture. Plaques frequently occur on the face, scalp, arms, back, legs, or buttocks.
Lupus pernio is a specific, often chronic form characterized by persistent, violaceous (purplish-red) plaques and nodules. These typically affect the nose, cheeks, ears, lips, and fingers, sometimes leading to disfigurement due to infiltration of underlying cartilage.
Erythema nodosum presents as tender, red, warm nodules, most commonly found on the shins, but can also appear on the knees, ankles, thighs, buttocks, forearms, face, and neck. This manifestation is usually acute and often resolves on its own within weeks to months.
Flat, discolored areas that are not raised are known as macules. Sarcoidosis can also emerge within existing scars, such as surgical scars, old injury sites, or tattoos, appearing as raised, discolored areas within the scar tissue. Less common forms include hypopigmented sarcoidosis, which manifests as lighter patches, and ulcerative sarcoidosis, characterized by open sores that may develop within existing lesions or on previously unaffected skin.
Common Locations of Skin Sarcoidosis
Skin sarcoidosis can appear on any part of the body, but certain areas are more frequently involved. The face is a common site, with lesions often observed around the eyes or mouth, and particularly on the nose and cheeks. The neck and scalp are also frequent locations for sarcoidosis lesions.
Lesions can appear on the trunk, including the back and chest. The limbs, such as the forearms, hands, shins, and feet, are also commonly affected areas.
How Appearance Can Vary
The visual presentation of sarcoidosis skin lesions can differ significantly among individuals and over time. Skin tone influences how lesions appear, leading to variations in color and visibility depending on complexion. The age and activity level of a lesion also affect its appearance; newer, active lesions may present differently from older, chronic ones.
While some sarcoidosis lesions may resolve without leaving a trace, others can result in lasting changes to the skin. These residual effects can include hyperpigmentation (darkening of the skin), hypopigmentation (lightening of the skin), atrophy (thinning of the skin), or scarring.