Histiocytic disease are a group of uncommon skin disorders which result from rapid and excessive growth of cells (medically known as cell proliferation).
The disease occurs in young dogs with mean age of five years and of any gender. Skin disorder is not restricted to a particular disease but systemic disease – where skin disorders spread into body systems – are predominantely reported in Bernese mountain dogs.
The histiocytic disorders can be differentiated into cutaneuos histiocytosis, Malignant histiocytosis and Systemic histiocytosis. Common symptoms associated with each form include
Cutaneous histiocytosis
Lesions involve skin and are subcutis (in the deep connective tissue of the skin)
Multiple nodules or plaques on the head and neck, trunk, extremities, and scrotum
No systemic organ involvement
Often takes a fluctuating, chronic course, where spontaneous regression of lesions may occur
Malignant histiocytosis
Pallor, weakness, shortness of breath (dyspnea) with abnormal lung sounds, and neurologic signs (e.g., seizures, central disturbances, back leg weakness)
Moderate to severe enlargement of the lymph glands and enlargement of the spleen and liver
Masses occasionally found in the liver and/or spleen
Eyes and skin are rarely affected
Malignant form affects older dogs, at a mean age of seven years
Malignant histiocytosis is rapidly progressive and usually fatal
Systemic histiocytosis
Marked tendency for skin, and lymph nodes
Multiple cutaneous (outer skin) masses are nodular, well-defined, and often ulcerated, crusted or hairless around the mass (alopecic)
Commonly found on the muzzle, nasal planum (black area of the nose), eyelids, flank, and scrotum
Moderate to severe enlarged lymph glands (lymphadenomegaly) is often present
Eye manifestations
Abnormal respiratory sounds and/or nasal mucosa infiltration
Organomegaly (organ enlargement) occurs with systemic involvement
Systemic histiocytosis is a chronic and fluctuating debilitating disease with multiple clinical episodes and periods without symptoms
Other symptoms and types
Most commonly affects Bernese mountain dogs
Golden retrievers, flat coated retrievers, and rottweilers appear to be predisposed, suggesting genetic factors
Lethargy
Anorexia
Weight loss
Coughing
Respiratory stertor (snoring sounds)
Dyspnea (shortness of breath)
Signs of systemic illness may not be present in dogs with cutaneous (skin) histiocytosis and in some dogs with systemic histiocytosis
