Can Infections Cause Hair Loss?
Your genes, hormone changes, and aging are the most common causes of hair loss. But some infections and infection-related conditions can also leave you with bald patches or thinning strands, either on your scalp or other areas of your body.
Most of the time, your hair will grow back after the infection heals. Sometimes, though, an infection can lead to permanent hair loss.
What Is an Infection?
Bacteria, viruses, and fungi are among the most common types of organisms that can cause infections (infectious agents).
Infections happen when one of them, or other tiny organisms, enter your body and start to multiply. This doesn't always cause disease, which only happens when your body's cells get damaged as a result. Once the disease sets in, you'll begin to show symptoms of the infection.
Some common infections that can cause hair loss include:
This common and usually mild infection is caused by a fungus that spreads easily from person to person. It can affect different parts of your body. On your scalp, it causes round (ring-shaped) bald spots that are scaly, red, and itchy. You might have a fever as well.
The fungus invades the skin on your scalp and may also get into your hair shafts. This causes hairs to break off. If the infection spreads, you get more and bigger bald spots.
Ringworm mostly affects children. But adults sometimes get it, too. You catch it through contact with infected people, animals, or objects.
To treat it, your doctor can prescribe a medicine to kill the fungus. You'll take it by mouth for 6 weeks or so, until the hair regrows. They may also prescribe a medicated shampoo to keep you from spreading ringworm to others.
If ringworm gets worse and isn't treated, it could lead to inflammation that can cause permanent bald spots.
Folliculitis is an infection of your follicles, the little openings in your skin from which hairs grow. The infection often happens after follicles are injured, such as by shaving. It's often caused by staph bacteria. But other bacteria, parasites, or fungi can also cause it.
It's usually mild and may go away within a few days. But some types of serious folliculitis infections could cause permanent hair loss.
- Pimple-like sores around hair follicles
- Itching or tightness
- Oozing, crusty sores
If the condition becomes serious, the infection can destroy hair follicles. This leaves bald patches where the hair won't grow back.
The way your doctor treats it depends on what's causing your infection. They might prescribe an antibiotic lotion or pills or an antifungal cream, shampoo, or pills. You might use a steroid medication to help with inflammation. Your doctor can also prescribe the oral acne drug isotretinoin.
This isn't technically an infection, but it's linked to a type of yeast (which is a fungus). Doctors believe that either the yeast itself or your body's reaction to it can cause temporary hair loss. It's not contagious. It tends to affect oily areas of your body, including your scalp, eyebrows, and mustache and beard area.
- A rash or patches of scaly skin
- Greasy areas of skin
- Dandruff that looks crusty or powdery
When you have seborrheic dermatitis, your skin produces too much sebum (the oily substance that keeps it moisturized). This can lead to irritation and itching. Scratching the itch may damage your hair follicles. That can also cause hairs to fall out.
You can treat this form of dermatitis with over-the-counter and prescription medicines. Some dandruff shampoos may help. Your doctor can also prescribe a medicated shampoo.
Once treatment gets the infection under control, your hair will grow back.
Piedra is a fairly rare type of infection that's caused by fungi. It affects the actual hair shaft, rather than the follicle or the skin on your scalp. It causes hard, stone-like bumps, or nodules, on the hair. In fact, "piedra" is the Spanish word for "stone."
There are two types of piedra: black and white. They're named for the color of the nodules that form on your hair. Each is caused by a different fungus.
With black piedra, the hard bumps tend to show up on hair shafts near your scalp. But they can also affect hair on your face, armpits, or groin. It's more likely to affect people in humid, tropical areas of Asia and South America.
White piedra shows up as white, beige, or brown nodules on your hair shafts. It most often affects the hair on your face, armpits, or pubic hair, but you can also get it on your scalp. It can look a lot like lice. It most often happens in wet, tropical climates, but people in other climates sometimes get it, too.
Most of the time, piedra doesn't cause serious symptoms. But sometimes it can weaken your hair shafts and cause hair to break off.
The main treatment for both types of piedra is shaving or clipping off the hair. Your doctor can also prescribe an antifungal, in the form of a shampoo or a pill. Your hair should grow back once it's treated.