By Gary M. White, MD
Calcinosis cutis (CC) is the deposition of calcium within the skin. It may occur at sites of tissue trauma (dystrophic calcinosis cutis). Within this category is trauma associated with calcium, e.g. at sites of electroencephalographic or electromyographic electrode placement using calcium-containing electrode conducting paste, extravasation of calcium chloride or calcium gluconate during IV administration, or occupational exposure (e.g. oil field workers with drilling fluid or coal miners or mine dust). Infants may develop small balls of calcium on the heel after heel sticks (for blood).
CC may also occur in association with various connective tissue diseases, most commonly systemic sclerosis (e.g. CREST). It also commonly occurs in dermatomyositis. Less commonly, it may occur in systemic lupus erythematosus even less commonly in discoid lupus erythematosus and extremely rarely in subacute cutaneous lupus erythematosus [Dermatology 1999;198;90]. A milia-like variant occurs in association with Down's syndrome.
A firm papule or nodule is felt within the skin. If sufficiently superficial, a whitish color is visible. Plain radiography is highly sensitive and is recommended for initial imaging of calcinosis associated with autoimmune connective tissue diseases [British J Dermatology 2014 May].
Dystrophic calcification is common in the legs of patients with chronic venous insufficiency. Ulceration is typical in more severe cases and the calcification may be extensive as calcification of skin tissues impedes wound healing and can be a risk factor for refractory ulcers [Acta Derm Venereol 2009;89(5):505].
Surgical excision may be performed but can induce more calcification, poor wound healing and infections. Digital calcinosis cutis in systemic sclerosis has been effectively treated with C02 laser vaporization of adjacent tissue and gentle removal of residual calcinosis. It has been reported that calcinosis cutis may be treated effectively with diltiazem e.g. diltiazem (1-3 mg/kg/day). Probenecid 25 mg/kg/day later increased to 1250 mg/day remarkably reduced the calcification in a 4 year old girl with elevated serum phosphate and uric acid [J Rheum 2001;28;1129].
Intralesional sodium thiosulfate injection has been reported effective in patients with dystrophic calcinosis occurring in various conditions including systemic sclerosis, lupus panniculitis, nephrogenic systemic fibrosis (NSF) and dermatomyositis [JAAD 2013;69;e146]. A group of 5 patients with systemic sclerosis and one with NSF were treated with IL STS and complete remission was achieved by week 12 in half of the patients. The other half had 80% reduction of their lesions [Acta Derm Venereol 2016; 96: 257–258]. The patients were treated with intra-lesional injections of sodium thiosulphate, 150 mg/ml, in the base of the calcification. Calcifications on the fingertips of less than 5-mm diameter were treated with a single injection of sodium thiosulphate, 150 mg/ml. More widespread calcifications complicated with ulcerations were treated with repeated injections every week for 4 weeks.
In a patient with calcinosis cutis associated with lupus panniculitis, IL STS at a concentration of 12.5 g/50 cc was used. After a ring block of lidocaine, 0.5 cc of STS was injected per 1 cm diameter circle every 5-10 mm. The patient experienced softening and shrinking of lesions after 2-3 injections per lesion.
Topical 10% sodium thiosulfate (formulated in a cold cream applied BID and occluded to affected areas) was used in a 6-year-old boy who had developed CC after infusion of calcium gluconate. 6 months later, the patient experienced complete resolution without local or systemic adverse effects [PD 2017;34;356].
Calcinosis Cutis (subcutaneous nodules) in a child with polymositis.
A rock hard nodule of calcinosis cutis in a patient with dermatomyositis.
Small grouped papules in a patient hospitalized for drug overdose and renal failure.