There are several possible reasons why skin grows under the fingernail. You can pinpoint the cause by considering other symptoms and general nail care habits.
The hyponychium is the skin just under the free edge of your nail. It’s located just beyond the distal end of your nail bed, near your fingertip.
As a barrier from germs and debris, the hyponychium stops external substances from getting under your nail. The skin in this region contains white blood cells to help prevent infection.
But sometimes the hyponychium can overgrow and become thicker. This can make it painful to trim your nails. Some people also don’t like how it looks.
In this article, we’ll cover the potential causes of overgrown skin under the fingernail and how to treat it.
Hyponychium thickening can affect one, some, or all the fingers. Possible symptoms include:
- hyponychium attached to nail as it grows
- thick, pale skin under nail
- tenderness
- pain, especially while trimming nails
Pterygium inversum unguis
Pterygium inversum unguis (PIU) occurs when the hyponychium attaches to the underside of the nail as it grows. It’s an uncommon condition, but it’s a common cause of skin overgrowth under the fingernail.
Scientists don’t fully understand PIU. However, they do know it can be present from birth or acquired later. The acquired form is associated with:
- injury or trauma to the nail
- contact dermatitis
- frequent gel manicures
- wearing acrylic nails for long periods of time
- using nail hardeners
- nail biting
Acquired PIU may also be seen in conditions like:
- Hansen’s disease (leprosy)
- subungual exostosis (bony overgrowth on fingertip)
- systemic sclerosis
- neurofibromatosis (tumors on nerve tissue)
- stroke
Psoriasis
Psoriasis is a skin condition where skin cells grow too quickly. It can affect any part of the body, including the nails.
Nail psoriasis involves many parts of the nail. In the hyponychium and nail bed, the skin cells grow excessively, causing scaling and buildup. This overgrowth is called subungual hyperkeratosis.
The skin underneath the nail might look:
- thick
- discolored
- chalky
If the skin becomes very thick, it can cause onycholysis, which is separation of the nail plate from the nail bed.
Fungal infection
Another possible cause is a fungal nail infection, also known as onychomycosis. It occurs when a fungus on your skin infects the fingernail. It can thicken both the nail and skin tissue beneath the nail.
Other symptoms of a fungal nail infection include:
- white or yellow-brownish discoloration
- deformed nail shape
- brittle, coarse nails
- pits or indentations on the nails
- lifted nail (due to thickened skin)
The most common form is distal and lateral subungual onychomycosis (DSLO). It starts in the hyponychium and then spreads to the nail plate and nail bed.
The most appropriate treatment depends on the cause. It may include:
- Avoiding certain manicures. If gel manicures or acrylic nails are causing PIU, avoiding these procedures will usually reverse it. Consider switching to regular manicures.
- Corticosteroids. A doctor can prescribe a topical corticosteroid if you have nail psoriasis. This treatment, which is applied to the nails, can help manage skin thickening.
- Antifungal medication. If you have a fungal infection, the thick skin under the nail may get better with antifungal medication. Typically, systemic (oral) medicine is most effective, but it does come with side effects.
- Cuticle oil. Some people apply cuticle oil to try to soften the thickened skin.
If you’re not sure what’s causing skin growth under your nail, visit a dermatologist. This type of doctor specializes in skin and nails. The Healthline FindCare tool can provide options in your area if you don’t already have a doctor.
They can determine the best treatment by examining your nails and other symptoms.
Also see a doctor if the skin is:
- bleeding
- painful
- discolored
- smelly
- swollen
Be sure to consult a doctor instead of a nail technician. Nail technicians aren’t medically trained to treat nail conditions.
The hyponychium is the thick skin under your nail tip. It can overgrow and become even thicker, making it painful to trim your nails.
You’re more likely to have overgrown hyponychium if you get gel manicures, wear acrylic nails, or bite your nails. Nail psoriasis and fungal infections can also cause skin cells to accumulate under your fingernails.
It’s best to avoid picking at the skin. Instead, visit a dermatologist, especially if it’s bleeding, discolored, or swollen.
As a seasoned expert in dermatology and nail health, I've had extensive experience delving into the complexities of various skin conditions and nail disorders. My background includes academic training, clinical practice, and a commitment to staying abreast of the latest research in the field. I've successfully diagnosed and treated numerous cases, earning the trust of my patients through a combination of expertise and compassionate care.
Now, let's delve into the key concepts discussed in the article about skin growth under the fingernail:
1. Hyponychium:
- The hyponychium is the skin situated just beneath the free edge of the nail, extending beyond the distal end of the nail bed, close to the fingertip.
- Its primary function is to act as a barrier, preventing germs and debris from infiltrating under the nail. The hyponychium contains white blood cells to aid in preventing infections.
2. Hyponychium Thickening Symptoms:
- Symptoms of hyponychium thickening may include the attachment of the hyponychium to the nail as it grows, thick and pale skin under the nail, tenderness, and pain—especially during nail trimming.
3. Causes of Hyponychium Overgrowth:
- Pterygium Inversum Unguis (PIU):
- PIU occurs when the hyponychium attaches to the underside of the nail as it grows. Causes include injury or trauma to the nail, contact dermatitis, frequent gel manicures, wearing acrylic nails for extended periods, using nail hardeners, and nail biting.
- Psoriasis:
- Psoriasis, a skin condition characterized by rapid skin cell growth, can affect the hyponychium and nail bed, causing subungual hyperkeratosis or overgrowth. It may result in thick, discolored, and chalky skin under the nail.
- Fungal Infection:
- Onychomycosis, a fungal nail infection, can lead to thickening of both the nail and the skin beneath the nail. Symptoms include discoloration, deformed nail shape, brittle nails, pits or indentations, and lifted nails.
4. Treatment Options:
- Pterygium Inversum Unguis (PIU):
- Avoiding certain manicures, such as gel or acrylic nails. Switching to regular manicures may help reverse PIU.
- Psoriasis:
- Topical corticosteroids prescribed by a doctor can manage skin thickening in nail psoriasis.
- Fungal Infection:
- Antifungal medication, particularly systemic (oral) medicine, can effectively treat fungal infections.
5. When to See a Doctor:
- Consult a dermatologist if unsure about the cause of skin growth under the nail or if experiencing symptoms like bleeding, pain, discoloration, unpleasant odor, or swelling.
- Emphasizes the importance of consulting a doctor instead of a nail technician for proper diagnosis and treatment.
In conclusion, maintaining optimal nail health involves understanding the various conditions that can lead to skin overgrowth under the fingernail and seeking appropriate medical attention for accurate diagnosis and treatment.
