Rash on the inside of my elbow

Inner Elbow Rash: Psoriasis or Eczema?

Q1. Recently, the doctor referred to the skin condition on my granddaughter’s inside elbow areas as psoriasis. Her mom took her to a dermatologist who called her condition eczema. Are these terms interchangeable? What is the difference between the two conditions? Thanks for the help.

Great question. Eczema and psoriasis are distinct entities, and most dermatologists feel that the two do not exist at the same time in the same patient. That is not to say that they do not look alike, because they can. They are both inflammatory conditions of the skin and, to some extent, they are treated similarly.

Eczema, specifically termed atopic dermatitis, is very common in children. With this condition, the littlest thing can induce redness and itching in the skin. (Eczema is uniformly more itchy than psoriasis.) The person then scratches the itchy spots, and characteristic red scaly patches develop.

Inside the elbow is a common location for eczema, not for psoriasis. Eczema likes to affect body parts that doctors call the “flexural surfaces” (neck, behind knees, inner elbows, etc.) whereas psoriasis likes the elbows, knees, scalp and belly button. There are five forms of psoriasis, but the most common, plaque psoriasis, appears as raised patches of red skin with silvery scales.

Q2. My daughter was given an allergy test on her back when she was 3 and was confirmed for certain seasonal allergies, dust, as well as cat allergies. I had my cat since before she was born and it hasn’t seemed to bother her as we have only had to treat her for seasonal allergies. She is now 7 and just adopted a kitten. Today, she went into the “kitten room” and sat down and came out shortly after with an itchy rash behind her knees. She has had this before and I treated it as eczema with cream and it goes away. I am just wondering if you think this could actually be an allergic reaction to the new kitten (which we’ve had for almost 2 months now). Thanks so much for you help!

— Kim, Virginia

Eczema, or atopic dermatitis, is an itchy rash that comes and goes and typically affects the backs of knees and insides of elbows in older children and teens (it affects different parts of the body in babies). The exact cause of eczema is not fully known, but allergies definitely play a role for some people. In very young children with severe eczema that is hard to control with standard creams and ointments, testing for food allergy should be performed. In older children, food allergy as a cause of eczema is rare, but flares in an eczema rash can be triggered by heavy exposure to inhaled allergens, or skin exposure to these allergens. Examples include exposure to cats and very dusty environments, or being licked by a dog, provided the person is allergic to these things. Eczema may also be worse during pollen seasons in a person with pollen allergy. In short, yes, exposure to the new kitten could have caused the increase in skin symptoms, especially because your daughter is known to be allergic to cats.

You mentioned that your daughter grew up with a cat in the house and didn’t seem to have problems before. It is probable that the presence of the cat was aggravating her allergic rhinitis and eczema all along, but when we are constantly exposed to something we are allergic to, the symptoms often change. Specifically, if a cat-allergic person does not own a cat, they may experience dramatic sneezing, wheezing, or swelling and redness of the eyes within minutes of exposure. However, if they live with a cat every day, then they are more likely just to have chronic nasal congestion. In the case of eczema, cat exposure may have been one of several chronic irritants that contributed to the persistence of symptoms.

The next point that is illustrated by your daughter’s situation is that symptoms can change again when people who have been living with an allergen have an interruption in exposure, such as when the pet dies or the grown child goes off to college. Then, when the person is exposed to a new cat or comes home from college on break, they develop more dramatic symptoms, like sneezing, wheezing, etc. I suspect your daughter’s sudden increase in skin itching was a version of this phenomenon.

Q3. My son has asthma. Recently, he has developed bouts with canker sores. Coincidently, his asthma has been acting up. Could canker sores aggravate his asthma? Also, can stomach irritation be an asthma inducer or trigger? His eczema had also been quite severe lately. Do flares of eczema usually mean flares of asthma?

Perhaps the sores in your son’s mouth coincide with a virus that is also aggravating his asthma. Patients with gastrointestinal issues such as reflux often develop chest tightness and wheezing. Eczema is an allergic condition, so it’s often exacerbated by allergens. And allergens also precipitate the worsening of asthma.

So it’s possible that the eczema and asthma are being triggered by the same thing, rather than one triggering the other. The same could be true of the canker sores and asthma. Whenever something affects one part of the body — whether infectious or allergic — other organ systems can also be affected.

Learn more in the Everyday Health Eczema Center.

What Is Causing The Rash On This Woman’s Inner Elbow?

This 28-year-old woman presented with a 2-month history of a rash that was confined to her right antecubital fossa and that had a burning sensation. Her medical history is complicated by a several-month history of interstitial pneumonitis that was being treated with azathioprine and a tapering dose of prednisone (now down to 10 mg daily).

What’s Your Diagnosis?
A. Atopic dermatitis
B. Dermatophyte infection
C. Impetigo
D. Contact dermatitis
E. Psoriasis

To learn the answer, go to page 2



Answer: E, Psoriasis
A diagnosis of psoriasis was confirmed by biopsy results. The patient was placed on rotational therapy with a potent topical corticosteroid and topical calcitriol, which resulted in complete clearing of the lesion. She did not have psoriasis lesions elsewhere on her body.
All of the other conditions listed (atopic dermatitis, dermatophyte infection, impetigo, and contact dermatitis) are reasonable differential diagnoses; the decision to do a biopsy also was reasonable.

There is no explanation for the asymmetric appearance of this patient’s psoriasis lesion, although her pharmacotherapy regimen of azathioprine and prednisone for interstitial pneumonitis probably was responsible for the atypical presentation of psoriasis.

David L. Kaplan, MD, is a clinical assistant professor of dermatology at the University of Missouri–Kansas City School of Medicine in Kansas City, MO, and at the University of Kansas School of Medicine in Kansas City, KS. He practices adult and pediatric dermatology in Overland Park, KS. He is the series editor of Dermclinic in Consultant.

This article was originally appeared in Consultant. 2016;56(11):999-1000.


Atopic eczema

Atopic eczema causes areas of skin to become itchy, dry, cracked and sore.

There are usually periods where the symptoms improve, followed by periods where they get worse (flare-ups). Flare-ups may occur as often as 2 or 3 times a month.

Atopic eczema can occur all over the body, but is most common on the hands (especially fingers), the insides of the elbows or backs of the knees, and the face and scalp in children.

Eczema on the ankle Credit:


Eczema on the back of the knees Credit:


The severity of atopic eczema can vary a lot from person to person. People with mild eczema may only have small areas of dry skin that are occasionally itchy. In more severe cases, atopic eczema can cause widespread inflamed skin all over the body and constant itching.

Inflamed skin can become red on lighter skin, and darker brown, purple or grey on darker skin. This can also be more difficult to see on darker skin.

Scratching can disrupt your sleep, make your skin bleed, and cause secondary infections. It can also make itching worse, and a cycle of itching and regular scratching may develop. This can lead to sleepless nights and difficulty concentrating at school or work.

Areas of skin affected by eczema may also turn temporarily darker or lighter after the condition has improved. This is more noticeable in people with darker skin. It’s not a result of scarring or a side effect of steroid creams, but more of a “footprint” of old inflammation and eventually skin tone returns to its normal colour.

Itchy Forearms

There are a number of reasons that you could have itchy forearms. Read on to learn about four common causes.

Contact dermatitis is a swollen, itchy, red rash caused by exposure to a substance (like poison ivy) or an allergic reaction to a substance (like jewelry made of nickel). Contact dermatitis usually clears up in two to four weeks.

Treatment for contact dermatitis includes:

  • identifying and avoiding the substance that caused the rash
  • applying topical steroid cream
  • taking oral medication such as corticosteroids, antihistamines, or antibiotics

Brachioradial pruritus

Brachioradial pruritus is a condition where you feel itching, tingling, stinging, or burning on one or both of your arms. It can be localized to the mid-arm, upper arm, or forearm.

The condition does not necessarily change the skin’s appearance, but rubbing and scratching the affected area might.

If you zealously rub or scratch your itchy arm or arms, you could eventually develop bruising, brown marks (hyperpigmentation) and/or white marks (hypopigmentation).

Experienced more often in sunny climates, brachioradial pruritus is caused by cervical nerve irritation combined with ultraviolet radiation (UVR) on the affected area.

Treatment for brachioradial pruritus includes:

  • avoiding exposure to the sun
  • applying topical medications such as capsaicin, mild steroids, anesthetics, antihistamines, or amitriptyline/ketamine
  • taking oral medications such as amitriptyline, gabapentin, risperidone, fluoxetine, chlorpromazine, or hydroxyzine

Eczema (also known as atopic dermatitis) is a chronic skin disorder that includes dry skin, itchiness, rashes, and scaly skin.

There’s no cure for eczema, but treatment can prevent new outbreaks and relieve symptoms such as itching.

Treatment for eczema includes:

  • using gentle soaps
  • moisturizing your skin a minimum of two times a day
  • limiting showers and baths to less than 15 minutes
  • showering with warm or cool water rather than hot water
  • drying your skin gently and applying moisturizer while your skin is still damp

Psoriasis is an autoimmune disease that speeds up the growth of skin cells. This causes scaly, red patches that are itchy and often painful.

Treatment for psoriasis includes:

  • topical treatments such as corticosteroids, vitamin D analogues, anthralin, topical retinoids, calcineurin inhibitors, or salicylic acid
  • light therapy such as UVB phototherapy, psoralen plus ultraviolet A, or excimer laser
  • medications such as retinoids, methotrexate, or cyclosporine

Itchy rash on forearms

The FP strongly suspected that this was a case of nummular eczema, based on the round shape of the plaques, but the location of the lesions suggested psoriasis. The FP also considered tinea corporis with psoriasis in the differential.

The FP checked the patient’s scalp, nails, and umbilicus for other signs of psoriasis and found none. He also performed a potassium hydroxide (KOH) preparation, which was negative for hyphae and fungal elements. (See a video on how to perform a KOH preparation here: http://www.mdedge.com/jfponline/article/100603/dermatology/koh-preparation.) To be sure that this wasn’t psoriasis, the FP also performed a punch biopsy. (The pathology subsequently came back positive for nummular eczema.) Ultimately, the yellow crusting, along with the round shape of the plaques, supported a diagnosis of nummular eczema. (“Nummus” is Latin for “coin.”)

Treatment for nummular eczema typically includes clobetasol, an ultra-high-potency corticosteroid. (The patient’s lack of response to the over-the-counter hydrocortisone was not unusual for nummular eczema because it is a low-potency steroid.) The FP in this case prescribed 0.05% clobetasol ointment to be applied twice daily to the lesions until the follow-up appointment 10 days later. At follow-up, the patient reported that the itching had almost completely resolved and the lesions were looking much better. The stitch from the biopsy was removed and the patient was told to continue using the clobetasol until the lesions completely resolved.

You can now get the second edition of the Color Atlas of Family Medicine as an app by clicking on this link: usatinemedia.com

Our skin is a complex structure of cells and proteins that constantly act to protect and maintain the body’s normal function. With age, there is a gradual decline in the skin’s ability to adequately sustain these processes. The epidermis thins and the amount of collagen previously abundant within the dermis steadily falls. Characteristic wrinkles develop and the skin becomes increasingly fragile. Langerhans cell numbers within the basal layer of epidermis drop, increasing the propensity towards cutaneous infection. It is therefore unsurprising that the prevalence of different skin disorders varies with age.

Clues in the history

The time-course of a rash can give a useful guide to the likely differential diagnosis. Infectious disease and drug reactions are likely to give a short history whereas psoriasis and eczema are likely to have been present for longer (Box 1). An additional distinction that provides useful diagnostic information is the presence and quality of itch (Box 2). Premalignant or malignant conditions such as Bowen’s disease will usually be asymptomatic. Psoriasis may often be associated with slight itch, but will rarely cause sleep loss due to scratching. Yet sleep loss due to itch is characteristic of eczema. Generalised itch (pruritus) is a common complaint among the elderly. The commonest cause of generalised pruritus is xerosis (dry skin), which is easily treated by avoidance of soap products and increased use of emollients. It is critical to distinguish cases of widespread itch with primary skin disease (usually inflammatory) from those with secondary skin disease caused by trauma from chronic scratching (Box 3). Treatment of pruritus relies on the identification of the underlying cause, although this may not always be possible (eg. senile pruritus). Aqueous cream with 1% menthol is useful in relieving itch in most cases whereas treatments such as phototherapy may be appropriate in specific cases. In generalised pruritus with excoriations, sparing of the central back is typical because the patient is unable reach this area to scratch without the use of an implement (Figure 1). In chronic scratching, characteristic eroded nodules may develop (nodular prurigo), which are commonly seen on the legs and arms. It is typical for there to be a predominance on the non dominant side. Localised itch may also occur as a consequence of chronic scratching, resulting in a focal area of lichenification and hyperkeratosis (lichen simplex).

Important pruritic dermatoses in the elderly


Scabies is an intensely itchy infestation by human-specific mites. Spread is predominantly through skin-to-skin contact, although mites can survive on clothing and linen for several days. Rapid spread within hospitals and other institutions is common, particularly among the elderly and other immunocompromised individuals. Itching is caused by allergic sensitisation to the mites, excrement or eggs which characteristically takes 2–6 weeks following infestation. Subsequent infestations give rise to a quicker onset of the rash and its symptoms. Erythematous papules and excoriations are characteristic. The characteristic scabies mite burrow is a linear grey thread-like lesion, often with a vesicle at one end, and represents the path of the female mite. Cutaneous lesions are distributed symmetrically and typically affect the inter-digital web spaces, the flexural aspect of the wrists, the axillae and waist. Nodules on the scrotum and penis, or around areolae are almost pathognomonic. The face is typically spared. Elderly patients who may be immunocompromised or immobile are susceptible to infestation by very high numbers of mites, which may cause thick scaly plaques. This form of scabies is commonly known as Norwegian or crusted scabies and is highly infectious. Surprisingly, the associated itch is often less intense. The atypical presentation can often lead to a delay in diagnosis. Once the diagnosis of scabies has been made the patient and all household contacts should be treated with permethrin 5% lotion or cream on the same day. This should be applied to the whole body including the head and neck in the elderly and the immunosuppressed. Particular care should be taken to ensure application under the nails and between the fingers and toes. Once applied, it should be left on for between 8 to 12 hours before washing off. Bedding, towelling and clothes should be washed above 50oC. The process is subsequently repeated a week later. In cases of allergy or resistance to permethrin, malathion 0.5% aqueous liquid can be used. Following eradication, crotamiton or topical corticosteroids can be used to control the itch, which may persist for several weeks after successful treatment.1


The onset of psoriasis shows a bimodal pattern. Late onset psoriasis (peak at 55 years) may often not show the characteristic well demarcated, scaly erythematous plaques over the extensors, scalp, postauricular sites and umbilicus (Figure 2). Late-onset psoriasis also shows a weaker genetic predisposition. Specific clinical findings such as nail changes and koebnerisation are useful positive findings. Solitary plaques of psoriasis need to be distinguished from Bowen’s disease, superficial basal cell carcinoma and dermatophyte infections.

Seborrhoeic dermatitis

Seborrhoeic dermatitis is a common condition typically confined to sites of increased sebum production. The pathogenesis of this disorder remains unclear, but an association with increased numbers of malassezia (pityrosporum) yeasts is recognised. Seborrhoeic dermatitis associated with Parkinson’s disease, mood disorders and HIV is often more treatment resistant.2 The scalp is the most frequently affected site and presents with a fine white scale and a diffuse mild erythema. Facial involvement is often striking by its symmetry, with an ill-defied greasy scale of the forehead, inner eyebrows, nasolabial folds and ears, external auditory canal and post-auricular areas. When present on the chest and intertriginous areas (axillae, groin and inframammary sites), lesions have an orange-brown colour and may resemble flexural psoriasis. More rarely a generalised form of the condition may occur, giving rise to erythroderma. Treatment is directed at reducing the inflammation and tackling the overgrowth of yeast. Low strength topical steroids, such as hydrocortisone 1% cream, in combination with an imidazole to the facial lesions and intertriginous zones is beneficial. Twice weekly use of ketoconazole shampoo to the scalp, as well as to the face and trunk help to maintain remission. Second-line therapies include moderate potency corticosteroids, calcineurin inhibitors (tacrolimus or pimecrolimus) and systemic imidazoles.

Asteatotic eczema

Untreated dry skin may progress to asteatotic eczema, which is frequently localised to the lower legs and characterised by a network of shallow cracks in the skin resembling crazy paving (eczema craquelé). In more extensive cases, extension with patchy involvement of the thighs and trunk occurs. The degree of pruritus is variable between patients. Late onset eczema in the elderly is often not associated with atopy. It is important to consider possible underlying causes such as pre-bullous pemphigoid, drug hypersensitivity and paraneoplastic disease in these cases. The avoidance of soaps and irritants, regular emollient therapy and topical corticosteroids are the mainstay of management. Severe cases may need systemic treatment with oral prednisolone or steroid-sparing immunosuppressants.

Mycosis fungoides

Mycosis fungoides is the commonest form of Cutaneous T-cell Lymphoma (CTCL), with a median age of onset of 55 years. Typically clonal T-cell populations are restricted to the skin thereby representing a “benign” skin limited lymphoma. The disease is usually mildly itchy and progresses from erythematous, fine scaled patches, typically on non-exposed sites to plaques and tumours of the skin. Lesions vary in size and may be difficult to distinguish from tinea corporis, eczema or psoriasis. A fine wrinkled appearance to the surface of affected skin is an important diagnostic clue (Figure 3). In severe cases clonal T-cell populations can be detected in the blood or bone marrow and the prognosis is worse.3

Drug rash

Drug hypersensitivity induced rashes are the commonest cause of new onset rashes in inpatients. Drugs commonly associated with hypersensitivity reactions include Beta-lactam antibiotics, anti-convulsants, allopurinol and sulphonamides. The typical presentation is of a mildly pruritic maculopapular rash starting one to three weeks after the initiation of a new drug. Initially the rash appears on the upper torso and spreads acrally, often becoming confluent. In a limited number of cases it may progress to complete erythroderma. The presence of fever, tender skin, blistering, mucosal involvement or systemic upset are important markers of severity. Early discontinuation of the causative drug is essential to prevent progression to a more severe drug reaction such as Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), Stevens-Johnson syndrome or Toxic Epidermal Necrolysis. Rarely, hypersensitivity rashes may develop several weeks after the discontinuation of a drug. Cross reactivity between drugs of the same group or similar structure can induce drug rashes within days of exposure despite never having encountered the drug before.4

Contact dermatitis

Contact dermatitis may be divided into either irritant contact dermatitis (ICD; skin barrier dysfunction) or allergic contact dermatitis (ACD; type IV T-cell mediated hypersensitivity). Both forms potentially pose a problem in the elderly population but ICD accounts for the majority of cases in this age group as it does in the younger population. ICD most commonly affects the hands due to hand washing. In the hospital setting, irritant dermatitis can be induced by the application of antiseptics (chlorhexidine) and low humidity. In elderly individuals with reduced mobility, faecal and urinary incontinence may give rise to severe dermatitis of the groin, genitals or buttocks. Unlike ICD, ACD is more itchy. Erythema and scaling are typical, with occasional vesiculation. Elderly patients with chronic leg ulcers are at high risk of sensitisation to topical medicaments or bandages and frequently present with lower limb erythema. Patch testing should be considered in dermatitis with a well defined border, or if affecting the face, hands or genitals because clinical evaluation is often unreliable. Avoidance of the irritant/ allergen and regular application of greasy emollient (such as 30% yellow soft paraffin/30% emulsifying wax) is often adequate. For severe cases topical corticosteroid ointments can be useful.6

Other important rashes

The development of a paraneoplastic rash maybe the first indication that an individual has an underlying neoplasm.

Localised rashes

Tinea corporis and tinea cruris

Dermatophyte (fungal) infections of the skin and nails are common in adults of all ages. Skin lesions are characterised by an itchy, erythematous and scaly lesion (“ring-worm”) except in cases inappropriately treated with topical steroids (tinea incognito). Lesions will typically expand with central clearing and a well defined leading edge, giving rise to an annular or arcuate appearance. Depending on the extent of inflammation, pustules may be also present at the edge of the lesion. The site should be scraped gently with a blade and the scale sent for microscopy and mycological culture. Limited infection can be treated topically with creams such as clotrimazole or terbinafine.

Superficial basal cell carcinoma and Bowen’s disease

Superficial basal cell carcinoma (BCC) and Bowen’s disease (squamous cell carcinoma in-situ; Figure 4) are both localised well defined discoid areas of scaly skin, usually 1–3cm in diameter. Differential diagnosis includes tinea corporis, eczema or psoriasis. Superficial BCCs show a predilection for the trunk whereas Bowen’s disease is usually on sun exposed sites such as the face, forearms and shins. BCCs usually show a raised edge which is best seen on stretching the skin. In trickier cases a biopsy is helpful in establishing the diagnosis. Management with topical chemotherapies such as 5-fluoruracil or topical imiquimod are often successful. Surgery or photodynamic therapy are also used.


Skin disease in the elderly accounts for a significant proportion of presentations to medical practitioners. This article aims to give the reader a firm basis with which to manage dermatoses in this age group. Thorough examination of patients presenting with red scaly rashes is essential in order to successfully diagnose and alleviate the patient’s symptoms, as well as to ensure that those features indicative of serious underlying pathology are not missed.

Conflict of interest: none declared

2. Malassezia, dandruff and seborrhoeic dermatitis: an overview. RJ Hay. British Journal of Dermatology 2011: 165 (suppl. 2): 2-8

3. Joint British Association of Dermatologists and U.K. Cutaneous Lymphoma Group guidelines for the management of primary cutaneous T-cell lymphomas. SJ Whittaker. British Journal of Dermatology 2003; 149: 1095–1107

4. Skin manifestations of drug allergy. M Ardern-Jones. Br J Clin Pharmacol 2011: 71(5): 672–83

5. Acral violaceous erythema and hyperkeratosis. A Fityan. Clin Exp Dermatol 2011; 36(3): 320–21

6. Guidelines for the management of contact dermatitis: an update. J. Bourke. British Journal of Dermatology 2009; 160: 946–54

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