Shedding skin from the feet is often alarming to the patient and the reason they may consult their podiatrist or general practitioner. There are many reasons why skin can peel and this article looks at some of the causes.
(Image used with permission)
Key questions to ask about skin peeling on the soles.
It's important as ever to take a good history as this is the solid foundation for a diagnosis. Typical questions might include:
How long has it been happening?
How often does it occur? (Monthly, seasonal, rarely)?
Does it involve the palms?
Does it itch?
How does it develop i.e. as blisters or sheets, redness etc.,
General medical history (including the skin) and medications.
Is there any family history?
Any recent activity - walking / sports
From here, a clinical examination for the feet can be helpful, including the footwear and don't forget to include the hands as well. When a fungal infection is suspected, skin scraping should be sought to rule out tinea pedis - a common cause.
Causes of skin peeling on the feet
Friction & rubbing
Some people's skin has the tendency to blister or peel more easily than others without any specific underlying condition. This can be exacerbated by sweating and footwear. It is important to assess the patient's activity levels and footwear to ascertain if it is responsible. Anecdotally, this appears more frequently in the summer months.
Infections
Localised infections can be a common cause of skin peeling. On the feet, tinea pedis is the most common reason. Most often caused by dermatophyte infection, the skin on the soles or between the toes may peel. This is occasionally accompanied by itching. It may be unilateral or bilateral. Assessment of the interdigital areas or nails may also indicate fungal infection. Treatment with appropriate antifungal creams should settle the infection within a few days.
Psoriasis
Psoriasis is a common inflammatory skin condition characterised by raised, scaly plaques with detachable silvery scales. It can affect any area of the skin but typically affects the extensor surfaces of the limbs and scalp in asymmetrical pattern. Psoriasis can be localised and affect the plantar surface typically as scale but occasionally as skin peeling. Around one third of patients with psoriasis have a family history of the disorder. Careful assessment of the patient's skin may reveal patches of psoriasis elsewhere (scalp, elbows and knees).
Contact dermatitis
Contact dermatitis is an uncommon condition on the soles of the feet. In order for it to arise on the soles two conditions must be met - excessive moisture and an allergen or irritant. Softening of the thick plantar epidermis from moisture allows ingress of the noxious agent which typically presents as an acute erythema, itching and shedding of the skin.
Identification and elimination of the causative agent is the key to improving the skin. Potent topical steroids in the short term can reduce the accompanying inflammation and then switching to weaker steroid preparations as the condition improves. Emollients can be a useful adjunct.
(Image from Kilmartin & Bristow 2015)
Medications
There are medications known to cause dryness of the skin (such as statins and diuretics). Peeling of the skin has been noted in patients taking retinoids and hydroquinone.
Keratolysis Exfoliativa (Ringed keratolysis)
This is a condition which primarily affects young adults of both sexes, whereby small ring-like white areas develop on the palms and occasionally soles which enlarge and result in skin shedding. Typically there is no irritation noted by the patient. The condition occurs mostly in summer and is frequently associated with hyperhidrosis (excessive sweating) with some suggesting it to be a mild form of pompholyx. The skin reforms gradually but then episodically the shedding may return. It is usually without any itching. There may be a family history. Under the microscope the skin shows clear separation of the stratum corneum from the rest of the epidermis.
Localised Epidermolysis Bullosa (LEB)
This is an inherited condition which begins in early childhood which manifests as blistering of the palms and soles as a result of minor trauma. Previously known as Weber-Cockayne Epidermolysis Bullosa, the condition is strongly linked to friction and so may occur following rubbing from an insole or shoes for example. Blisters heal without scarring but the skin on the soles and palms may thicken. The autosomal dominant condition results in genetic mutation of keratin filaments 5 and 14, which lead to an increased risk of blister formation due to friction, worsened by hyperhidrosis.
Exfoliative Ichthyosis
Ichthyosis is a group of hereditary skin conditions characterised by dry and scaly skin (see my earlier blog). Exfoliative ichthyosis is an autosomal recessive form of the condition which leads to shedding of the skin, precipitated by minor trauma and moisture. The condition can occur on the feet but generally involves the whole integument.
Acral Peeling Skin Syndrome
Acral Peeling Skin Syndrome (APSS) is a rare autosomal recessive dermatosis characterised by frequent skin shedding of the palms and soles. It usually begins in early childhood and almost always affects the palms and soles, although the arms and legs can be involved as well. APSS tends to be worse in the summer months. The prevalence of the condition is unknown. APSS is caused by a genetic defect on chromosome 15, the transglutaminase 5 (TGM5) enzyme introduces isopeptide bonds into the structural proteins of the epidermis leading to cleavage between the stratum granulosum and stratum corneum. Inflammatory and non-inflammatory types have been reported to exist. Differential diagnosis from localised epidermolysis bullosa is required.
Acral Peeling Skin Syndrome in a teenager
(Image from Cliefe, Penrose and Bristow 2015)
Keratolytic Winter Erythema
Also known as Oudtshoorn disease, is an autosomal dominant condition originating from families in the Oudtshoorn district of Cape Town. The condition manifests as palmo-plantar peeling from infancy but improves with age. Peeling often presents as circular areas of detachment coalescing to large areas on the hands and feet. Itching, pustulation and erythema often accompany the condition
Environmental Causes
A number of external factors such as dry heat, excessive cold weather, drying due to over-bathing, exposure of the foot to strong chemicals, soaps and alkalis may also cause skin peeling on the soles.
Kawasaki Syndrome
Kawasaki Syndrome a rare auto-immune disorder affecting children under five. It presents as an acute febrile illness. Peeling of the skin on the hands and the feet can frequently be observed as part of the condition.
Other conditions which can lead to peeling of the soles include:
Reactive Arthritis (Previously referred to as Reiter's disease). A psoriaform rash which can be accompanied with peeling of the plantar area.
Hand Foot syndrome (see my previous blog). Observed in patients undergoing chemotherapy with peeling of the palms and soles, often accompanied by pain and blistering in severe cases.
Management
Management of peeling skin depends on the cause. For most addressing the underlying cause can lead to alleviation of symptoms but for most conditions such as APPS and keratolysis exfoliativa, treatment is only supportive with the use of urea based emollients.