Bryn Mawr Dermatology

Villanova, PA | Collegeville, PA
Chesterbrook, PA

Dermatitis / Rashes

Dermatitis / Rashes


Skin is strong. Skin is beautiful. And because skin’s number one job is to protect your insides from microbes and the elements, it sees a lot of abuse. The environment is full of bacteria, pollutants, viruses, and other irritants, all of which are prevented from crossing the protective layers of your skin in order to ward off infection and disease. This amazing waterproof shield, although very tough, can sometimes bear the ill effects of the constant attacks it is fending off. Many physical assaults, whether it be a splinter, a stubbed toe, or a surgery, result in a wound that is identified and healed by your body’s immune system. Other types of invaders can cause superficial skin irritation otherwise known as dermatitis. The prefix “derm” refers to skin and the suffix “titis” means inflammation. Many different types of dermatitis exist, and many appear very similar and may even share symptoms, but have different pathologies.

Identifying and treating disease states of the skin is Bryn Mawr Dermatology’s specialty. If you notice a red itchy patch that won’t resolve, you develop little blisters that hurt, or you notice hives that chronically keep returning, it might be a good time to call and book an evaluation and management appointment with us. Most conditions that are identified by skin symptoms, are indicative of disease states that are restricted to the skin and underlying tissues. Most do not progress to involve other body systems; however, there are certain scenarios in which a rash on the skin can be an indication that something is not quite right with your immune system, or that you have an infection that is threatening to spread. Getting that rash diagnosed quickly may help prevent any health troubles down the line. Either way, discrete rash or something more, the experts at BMD can help relieve your symptoms.


Any time your skin is not 100% healthy it can be concerning. In the instance that you have a rash that is not resolving or is worsening despite any over-the-counter remedies you may have tried, it’s probably a good idea to see a skin specialist. In the case that you develop symptoms that are systemic, like a fever, shortness of breath, joint pain, or nausea in tandem with your rash, seek attention as soon as possible.

For dermatitis treatments in Villanova or Collegeville, contact our dermatologists today at 610.525.7800! or easily book an appointment by clicking the Schedule Now button at the top of the page. We look forward to caring for you!


We all want skin that glows with health. Any mark or irritation on the skin that mars it’s appearance can be an emotional impediment as well as a medical one, and although most skin concerns are not life threatening we take them very seriously. In addition to functioning as a barrier between our insides and the environment, skin helps to regulate temperature and retain water, it allows your body to feel sensations like warmth, cold, pressure, itching and pain. The skin itself is a complex structure with three main layers: the epidermis, dermis and subcutis from the outermost layer to the innermost.

The epidermis continually renews itself by creating new cells from the bottom up, causing superficial cells to shed on a regular basis. It contains specialized cells called melanocytes that store a black pigment called melanin and define the color of our skin in addition to protecting it from UV exposure. There are also lymphocytes that play an important role in fighting germs and Merkel cells which are specialized sensory cells that allow us to sense pressure.

The dermis is the middle layer of the skin, and is constructed of a dense network of connective tissue including collagen and elastin fibers which gives skin its framework and ability to stretch. It also contains the majority of your sensory cells and your sweat glands, which in tandem identify heat, cold, and pain and regulate your body’s temperature. It is laced with tiny blood vessels called capillaries which supply the surrounding cells with oxygen and nutrients. Your hair follicles also reside in the dermis.

The subcutaneous layer is composed mostly of fat and water. It provides the body with insulation and acts as a shock absorber, protecting the bones and soft tissues beneath. The fat cells produce hormones essential to the body’s regulatory functioning.

There are a lot of components of healthy skin, including the other systems of your body working in tandem to provide it with nutrients and feedback. If any one of these is not functioning properly you may develop visible confirmation of this disturbance on your skin.


Rashes are some of the trickiest dermatological concerns to diagnose due to the variety of causes and the fact that the same disease can present in many different forms depending on the individual. Most dermatitis can be assessed visually by a trained dermatology specialist. First, a complete medical history is taken from the patient and then many pertinent questions are asked regarding the rash itself. Essential pieces of information collected are:

  • Location – Where is the rash now? Did it start there, or has it spread/relocated since the patient noticed it?
  • Signs & Symptoms – What does the rash look like (i.e. red, swollen, scaly, oozing) and how does it feel (i.e. itchy, painful)?
  • Duration – How long has this rash been present?
  • Timing – Is the rash consistently visible or does it come and go
    Context – Does any event change the symptoms, either for the worse or better? Example: the rash is worse when it is cold out.
  • Treatments – What has the patient tried to treat the rash with (including prescriptions and over the counter remedies), and have any of these helped or made the rash worse?

If the visual assessment alone is not sufficient, your provider will utilize accessory testing to nail down the diagnosis. This may consist of scraping the superficial skin and looking at cells under a microscope, bloodwork, or a biopsy of the deeper layers of skin. For certain rashes that have been determined to be contact dermatitis – meaning that they are being caused by the skin coming into contact with an irritant – the provider may also suggest patch testing in order to identify what your skin is sensitive to. This further assessment can help determine the root cause of the skin irritation and provide the doctor or PA with information that will allow them to decide which treatment(s) will be best. Most of the time dermatitis is transient and will resolve with the appropriate medication or lifestyle change; however, some dermatitis is categorized as chronic. In these cases, the team at BMD will suggest ways to manage your symptoms and prevent flare-ups.

Types of Rashes

There are thousands of diagnoses in the medical world that identify unique rashes. The following are some of the most common categories of dermatitis that we come across.

Thirty one million Americans suffer from some form of eczema. This group of conditions tend to present as itchy, dry, red patches that occur on any part of the skin. Eczema affects people of all ages, genders and skin types, but tends to be more prevalent in those with generally sensitive skin. It can present acutely or, more commonly, come and go throughout your lifetime. Scientists believe that eczema is secondary to a combination of genetic predisposition and external irritating factors. When your skin comes into contact with a “trigger” your immune system becomes active and causes inflammation at the site. It is this inflammation that causes the symptoms common to most types of eczema.

The seven different types of eczema are:

  • Atopic dermatitis – the most common type of eczema, originating from within the body due to unknown factors
  • Contact dermatitis – dermatitis due to contact with an irritant, common irritants are plants, metals, dyes and cleaning products
  • Neurodermatitis – skin inflammation caused by chronic scratching; the itching sensation can be caused by anxiety, nerve injury or dry skin
  • Dyshidrotic eczema – commonly occurs on the hands a feet and presents as small itchy blisters, the cause is unknown
    Nummular eczema – appears as scattered coin-shaped patches that itch and can result in a broken skin barrier, responds well to treatment
  • Seborrheic dermatitis – commonly known as dandruff, an immune response to an overabundance of yeast on the skin causes flaking skin, itching and redness
  • Stasis dermatitis – occurs in the lower limbs when circulation is poor and fluid pools causing edema (swelling), if left untreated it can cause permanent skin changes
Drug Allergies
When your body responds to a medication as if it is a foreign invader you may see the physical manifestations of this response as a rash or hives. Unlike contact dermatitis, this rash will be widespread due to the fact that the irritant has been ingested, inhaled or injected into the body rather than just contacting a discrete patch of skin. Penicillin is one of the most common prescription medications to cause a drug allergy, and its use has declined over the years due to this fact. Many other drugs, including prescriptions, over-the-counter medications, and homeopathic remedies can cause an individual to respond with an allergic reaction. Your body can react to the drug on your first encounter or you can develop a sensitivity to the drug over time. Other signs of a drug allergy to watch out for are breathing problems, swelling, vomiting and in the most severe responses anaphylaxis. Drug allergy symptoms that are confined to the skin only can be treated, but once they evolve into systemic symptoms can become deadly, so they are best identified and avoided.
Bites & Stings

The majority of bites and stings that cause skin irritation are attributed to arthropods (invertebrate animals with an exoskeleton – think spiders, ticks, bees and other familiar insects). These animals deliver bites and stings that fall into one of two categories: venomous or non-venomous. Both types of arthropod attacks breach the skin barrier and cause irritation at the site that can range from a small red welt to a significant rash that itches, burns and can be temporarily painful. Most of us have experienced a mosquito bite that swells and itches, and know that if left untreated it will resolve on its own. That is true of most arthropod bites and sting.

In rare circumstances, arthropod attacks have the potential to cause systemic reactions, and in these instances you should urgently seek medical care. Ticks infected with bacterium Borrelia burgdorferi can transmit Lyme’s disease to the recipient of their bites if they are not treated with antibiotics soon after the encounter. Venomous black widow spider bites have the potential to cause serious systemic neurotoxicity which can be life threatening. Any type of bite or sting can lead to an infection due to the nature of the injury. It is best to seek medical care if you notice any injury that is getting worse instead of better, if it is spreading, or if you develop systemic symptoms.

Common Non-Venomous Bites & Stings

  • Mosquito – causes round puffy bump at the site of each bite, often itchy
  • Flea – causes small discolored bump on skin, often itchy and come in clusters; can transfer from one host to another
  • Tick – most commonly present as an individual round welt that itches; it can develop into a “bull’s-eye” rash that has accompanying flu-like symptoms if an infection occurs
  • Bed Bugs – straight rows of small, red, itchy bites most commonly found on the extremities; spread from object to human rather than human-to-human (ex. bedding-to-human)
  • Scabies – clusters of red, pimple-like bumps, commonly found in skin folds; caused by the burrowing of microscopic mites; contagious via skin-to-skin contact

Common Venomous Bites & Stings

  • Bee – identified by a single instant sharp pain followed by a red welt that continues to burn due to injected venom; to reduce symptoms remove the embedded bee’s stinger as soon as possible
  • Wasp, Hornet and Yellow Jacket – one or more painful red welts that continue to burn due to injected venom; they do not lose their stingers when they attack
  • Certain Spiders – red, inflamed bump that is painful and becomes increasingly so with time; can develop into an ulcer; you may develop systemic symptoms

Anytime your skin barrier is broken there is a chance of developing an infection. The risk of infection increases with the size of the wound and the length of time that the wound is exposed to the environment. The experts at Bryn Mawr Dermatology see a wide variety of skin infections that range from the invasion of bacteria into a laceration, viral infections at the site of microscopic skin irritation, to fungal or yeast infections caused by an overgrowth of normal skin flora. Some of the signs of dermal infection are pus or other fluid expressing from the site of injury, red, tender, swollen skin, a pimple-like growth with a golden crust, or small scattered blisters. When an infection advances it can start to cause more systemic symptoms like fever or disorientation; at this point it is imperative to seek urgent medical care as certain infections are deadly.

Some common skin infections we see are:

  • FUNGAL & YEAST INFECTIONS – most likely to develop in chronically damp areas of the skin like feet or skin creases; develop from normal skin flora that is overactive; are usually easily treated with topical or oral medications; some colloquial names for these types of infection are: athlete’s foot, jock itch, ringworm and nail fungus.
  • BACTERIAL INFECTIONS – any skin inflammation caused by an overabundance of bacteria; frequently occur at the site of an injury; normally easy to treat with oral or topical antibiotics; common bacterial infections are Impetigo, Methicillin-resistant Staphylococcus aureus (MRSA), and Cellulitis
  • VIRAL – any skin inflammation caused by a virus or viral particle; they can range from mildly irritating to severe and life-threatening; not curable with topical or oral medication, but symptoms are often managale with other treatments; common viral infections are Varicella (chickenpox and shingles), Verruca Vulgaris (the common wart), Molluscum contagiosum, and Hand, foot, & mouth disease
  • AUTOIMMUNE – a disease that occurs when your body’s own immune system attacks your own tissue and organs; usually has systemic symptoms that are occasionally accompanied by skin symptoms; the baseline disease is not curable, but symptoms can be controlled with medications and behavior modification; common autoimmune diseases with dermatological symptoms are Psoriasis and Lupus

Treating Dermatitis and Rashes in Villanova and Collegeville

In addition to being itchy, painful or tender, the symptoms of skin irritations are visible. Wearing the signs of dermatitis on your skin can be embarrassing and affect social interactions. The good news is, when you seek care from a well-respected and practiced physician team like the one we have at Bryn Mawr Dermatology, most inflamed skin states are manageable if not curable. The first step is diagnosing your dermatitis. Once that is complete, your provider will identify the most effective way to treat your symptoms. More often than not, a simple prescription cream or wash will serve to dissipate your ailment. Occasionally, in the cases of advanced infection or other aggressive dermatitis, an oral medication will be required. Sometimes, we have to problem solve to find what will work for you best and only arrive at the ultimate treatment after one or two others have failed. This can be frustrating, but is an essential part of the health-care process because so many rashes look alike and each individual responds differently to treatment. The doctors and PAs of BMD are at their best when they are challenged to think outside the box and coordinate with other specialists in order to help patients with particularly perplexing disease states. Know that during the process, we will respect your concerns and remain attentive to your whole-body health.

Your Skin is Our Business.



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