CONDITION
Calcinosis Cutis
Calcinosis cutis describes a process in which calcium salts are deposited in the skin, forming firm nodules, plaques, or crusty patches that can appear across different parts of the body. These deposits develop when the normal balance that keeps calcium in solution is disrupted, most often as a complication of other conditions rather than appearing on their own. Owners typically notice raised, hard lumps or gritty areas under the skin that may feel like small stones, sometimes with chalky material visible at the surface or seeping from the skin. The areas can be uncomfortable, and the overlying skin may become inflamed, ulcerated, or prone to infection. In dogs, this pattern is most commonly seen in animals with hormonal imbalances, particularly those affecting the adrenal glands, though other triggers exist. This page explores the signs that may raise suspicion, the mechanisms that lead to calcium deposition in different scenarios, the investigations that help clarify what is driving the process, and the range of approaches used to manage both the deposits and the underlying causes.
Why this matters now
Calcinosis cutis tends to appear in middle-aged to older dogs, typically between six and ten years, though the age range can vary depending on the underlying cause. Dogs with Cushing's disease or those receiving long-term corticosteroid therapy are at greatest risk, and certain breeds, including Boxers, Boston Terriers, and German Shepherd Dogs, appear more susceptible. The condition is less commonly seen in cats, where it may occur in association with chronic kidney disease, dietary imbalances, or following injections at specific sites.
The deposits often begin as small, isolated nodules that may go unnoticed for weeks or months before becoming more obvious or widespread. In some animals, the lesions remain stable once the underlying trigger is controlled, while in others the deposits continue to enlarge or new areas appear, particularly if the hormonal or metabolic disturbance persists. The rate of progression varies widely; some cases develop slowly over many months, others progress more rapidly, and a minority may improve spontaneously if the triggering condition resolves.
Signals & patterns
Early signals
Firm lumps beneath the skin
Owners may feel small, hard nodules, often on the neck, back, or groin, that do not move freely and feel denser than the surrounding tissue. These can be mistaken for ordinary lumps at first, but they tend to feel gritty or stone-like when pressed.
Roughened or thickened patches
The skin over affected areas may become slightly raised, rough to the touch, or lose its normal pliability. These patches can be subtle initially and may only be noticed when running a hand over the coat during grooming.
Localised hair loss
Hair over the deposits may thin or fall out, leaving bald patches that reveal the underlying firm or whitish tissue. The hair loss is typically gradual and may not be symmetrical.
Mild discomfort on touch
Some dogs flinch, pull away, or show mild sensitivity when the affected areas are pressed, suggesting that the deposits are causing low-grade irritation even before the skin breaks down.
Later signals
Ulceration and crusting
As deposits enlarge or push through the skin, the surface may break open, forming ulcers that weep chalky or gritty material. These wounds can be slow to heal and prone to secondary bacterial infection.
Widespread lesion formation
In cases where the underlying condition is poorly controlled, new deposits may appear across multiple body regions, creating a patchwork of hardened areas, some of which coalesce into larger plaques.
Persistent inflammation and infection
The skin around established deposits may become red, warm, and swollen, sometimes discharging pus if bacteria colonise the damaged tissue. Recurrent infection can contribute to ongoing discomfort and delay resolution.
Click to read about the biological mechanisms
How this is usually investigated
Options & trade-offs
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