Hotspots are localized areas of skin inflammation characterized by a rapid onset, intense irritation, and a distinctly moist surface. These lesions appear quickly, often within hours, and are typically red, painful, and warm to the touch. The condition is a reaction pattern in the skin, not a singular root disease. This intense inflammatory response is triggered by something that causes the individual to persistently scratch, lick, or chew a specific area of the body.
Initial Environmental and Physical Irritants
Hotspots frequently begin with a minor physical irritation that prompts the initial urge to scratch. Excessive moisture retention against the skin is a common trigger, especially in individuals with dense coats or those who frequently swim. This trapped moisture compromises the skin barrier and creates a favorable environment for irritation to develop. Friction, such as rubbing caused by poorly fitting collars or harnesses, can also initiate the inflammatory process. Localized trauma, including insect bites from fleas, mites, or other small arthropods, provides a physical spark that leads to intense localized itching and self-trauma that exacerbates the lesion.
Underlying Allergic and Immune Sensitivities
Underlying immune system sensitivities determine which individuals are most susceptible to developing hotspots, such as those with environmental allergies (atopy) causing systemic hypersensitivity to common allergens. These systemic sensitivities lower the skin’s tolerance threshold, making it prone to an exaggerated inflammatory response even to minor irritants. Food sensitivities also contribute by causing chronic itchiness and inflammation that predisposes the skin to localized trauma. When the immune system is already on high alert, a simple irritant can trigger an overwhelming sensation of pruritus, making self-inflicted trauma more likely to breach the skin’s protective barrier. Controlling these chronic immune sensitivities is necessary in preventing the recurrence of acute moist dermatitis.
The Role of Secondary Bacterial Infection
The invasion of opportunistic bacteria transforms the lesion into an infection, as persistent scratching and licking damage the skin and create an open wound. This self-trauma introduces bacteria, most commonly Staphylococcus species, into the deeper tissue. The resulting wound is warm, moist, and often covered in exudate, providing an environment for bacterial proliferation. This rapid bacterial growth leads to a superficial skin infection, or pyoderma, causing intense pain, swelling, and discharge. The resulting intense itchiness encourages further self-trauma, creating a self-perpetuating cycle that causes the lesion to expand rapidly, sometimes within hours.
Breaking the Cycle and Preventing Recurrence
Effective management of acute moist dermatitis involves breaking the self-trauma cycle and addressing the infection. The hair surrounding the lesion must be clipped to allow air circulation, and the site is cleaned with antiseptic solutions to reduce the bacterial load and remove debris. Depending on the severity, treatment may include topical medications containing anti-inflammatories or systemic antibiotics to control the deeper bacterial infection. For long-term prevention, the focus shifts to controlling underlying causes, such as strict parasite control to eliminate flea and mite irritation. Managing chronic allergic skin disease through dietary changes or anti-allergy protocols is necessary, as is consistent grooming to prevent moisture retention and friction.