Sheila Elcott asked: I have an 11 year old red fox lab boy who keeps getting a build up of black coloured dandruff type patches under his chin & his manly areas. Up to date with spot on. Is it his age & lack of my grooming care? After bathing & removing said patches the skin clears. He has hip & elbow dysplacia to boot. Tnx Answer: Hi Sheila, thanks for your question. Skin problems in dogs can be really frustrating to deal with, so I'll go through some of the possibilities, then talk about how they can be investigated and managed. So, what can cause patches of black dandruff material to appear? There are a number of possibilities that spring immediately to mind:
- Flea dirt. Flea droppings are black flecks, sometimes comma-shaped.
- I know you're up to date with spot-on, but there are a wide range of different products out there, some of which are more effective and longer-lasting than others. In addition, most spot-ons are water soluble, so regular bathing or swimming will reduce their effectiveness.
- You'll very rarely see a live flea unless there's a really severe infestation. To check it out, try the wet paper test:
- Scrape some of the black material onto a sheet of wet white paper.
- If it goes red, it is probably a flea dropping - they're basically just dried digested blood.
- Scabs. As blood dries, it turns black and crumbly. It can be caused by:
- Lice. Heavy louse infestation can cause scabbing where the parasites suck.
- Skin infections. In these areas, this would typically be a skin fold infection, where saliva or moisture is trapped against the skin, damaging it and allowing infection to become established.
- Allergic reactions (e.g. contact dermatitis). Reactions to products such as surface cleaners, pesticides, some plants, etc etc; typically affect the high-contact surfaces - chin, elbows, hocks and belly.
- Sebaceous matter. Sometimes, excessive secretion of sebum may give the symptoms you're discuss. This may be due to sebaceous adenitis (an inflammatory disorder), or simply from aging changes.