When performing a skin exam to rule out skin cancer in a patient,please do not forget to examine

the feet including  the soles of the feet and toenails.

                  And,it is certainly not true that people with darker skin tones are immune to skin cancer,although some

people with darker skin do develop skin cancer less often than those with lighter skin.

                  However,in my many years of practice I have seen more than a few patients with darker skin types

who turned out to have a very dangerous type of skin cancer called malignant melanoma.

                 And,statistics show that in  people with medium to dark skin which may even include some Hispanic and Asian people,

skin cancer makes up 4-5% and 2-4% of all cancer cases respectively.

                However, when  skin cancer develops in people with darker skin types,it commonly appears  in areas of the skin with

less pigment such as the mucous membranes of the mouth,finger and toe nails,soles of the feet,palms of the

hands,the anogenital region whiuch is the area around the groin and anus, and the lower legs.

                But,an important teaching point here  is that skin cancer often develpos on the sole of the foot in people

with darker skin tones since this accounts for 30  to 40 % of all their skin cancer cases according to the Skin Cancer

Foundation.

              And,a timely diagnosis is crucial before skin cancer reaches its later stages.

              So, Don't Forget the Feet.

                 Some  of the most promising new therapies for warts (human papilloma virus-HPV) involves

using medications to prevent them from disabling the body's immune system

               Now,it is thought that warts,  may, similar to cancer , release substances known as immune

checkpoints which prevents the body's immune system from attacking and destroying them  before

thjey are able to establish a foothold on or in the body.

               Recent research indicates that recalcitrant warts in particular released an immune checkpoint

such as PD-L1(programmed cell death) which attacks the body's immune system  and prevents the

body from killing the wart virus.

               And, it is believed that drugs called immune checkpoint inhibitors can energize the immune

system to kill  viral warts  by blocking immune checkpoint proteins such as PDL-1 and PD1.

             Therefore,it is hoped that we may be able to use these immune checkpoint inhibitors

to help the body's immune system to recognize the human papilloma virus. and destroiy it.

            When these drugs are given internally to fight various types of cancer such as the merkel

cell carcinoma  and malignant melanoma(see previous articles) ,they can be very effective but

can also have many potential side effects.

            Hopefully, a topical(not internal) form will be developed and not lead to any untoiward

effects.

             Prurigo nodularis is a chronic skin disease that causes hard, itchy lumps or nodules to form on the  skin.

            And, the itching can be so intense that it causes people to scratch themselves to a point of bleeding or

pain and the scratching can cause more lesions to appear. And,these.skin nodules or lumps usually appear in

a symmetrical  pattern in easy to reach places  such as the arms,legs or upper back.

           Therefore, prurigo nodularis causes a scratch itch cycle since the more you itch,the more you scratch

and the more yopu scratch, the more you itch. Consequently,treatment includes  topical(applied on the skin),

oral and intralesional(ie,injected) corticosteroids in an allemp to alleviate the inflammation and the sense

of itching.

         In addition, antihistamines and anti-anxiety drugs  are also given orally as well as a drug notorious for

causing  birth defects called thalidomide-although this drug and its derivatives can only be given to women

of child bearing age if they are on strict birth control  measures.

         Also, there are small case studies showing the potential for  the use of methotrexate,a folic acid

antagonist widely used for autoimmune inflammatory disorders such as psoriasis.

        However,before treatment especially in recalcitrant cases,a thorough history and physical exam as well

as lab work should be done to rule out underlying medical conditions such as severe anemia or liver and

kidney disease or a type of malignancy called lymphoma as well as HIV(human immunodeficiency virus).

        In my practice,I have even done skin biopsies on various skin nodules to rule out a type of skin

cancer called squamous cell carcinoma which can eventuate from chronic itching and skin irritation.

      In conclusion,I would urge anyone with long  term itchy, crusty skin   lesions to contact their

healthcare provider  to ascertain that they are not coming from an internal disease.

,

                The basal cell carcinoma is the most common of all skin cancers,accounting for 80 percent of

non-melanoma skin cancers while the squamous cell carcinoma accounts for nearly 20 percent. 

And,non-melanoma skin cancers are more common in men with squamous cell carcinoma affecting

2 to 3 times as many men as women  while basal cell carcinoma occurs at a rate of 1 1/2 times of

men to women.

                 The American Cancer Society estimates that in 2019 an approximate 57,000 cases of

melanoma will be diagnosed in men and about 39,000 cases in women.And,the incidence of

melanoma is higher among men across most racial/ethnic populations.

                Since most cases of skin cancer link to sun exposure ,it naturally follows that the

incidence increases with age.And,the incidence of melanoma  increases after age 19 and peaks

for individuals older than 85. between 2011 and 2015 the median age for the diagnosis of melanoma

was 64.

               In addition, the incidence of specific types of skin cancer varies according to race and

ethnicity.Consequently, the risk is more than 20 times higher for the white population than for people

with darker skin such as black,American Indian/Alaskan natives,Hispanic and Asian/pacific islander populations.

And,this is due to the photoprotection provided by increased melanin in the epidermis(outer skin layer) 

of individuals with darker skin,which can filter twice as much  UV radiation as the epidermis of white 

individuals.

              As is true for the white population,basal cell carcinoma is the most common skin cancer  among

Hispanic and Asian populations . In contrast,squamous cell carcinoma is the most common skin cancer

in the black population and melanoma is the third most common skin cancer  among all racial/ethnic

populations.

             And, the highest rate of melanoma is found amiong white men and the lowest is among black

women. Although melanoma is predominate among white men compared to white women,the incidence

of melanoma in men and women is similar in black,Hispanic, and Asian/pacific islander population.

            In addition to sun exposure and radiation exposure,the risk of skin cancer is also inluenced

by co-morbid or other conditions such as non-healing ulcers and tatoos as well as arsenic in the

well water . People whose immune systems are compromised either

by cancer or the drugs used to treat it are also at increased risk for skin cancer.

            Also, skin cancer can develop in 30 to 70 % of  organ transplant patients-with a 100 fold

increase for squamous cell carcinoma ,a 24 fold increase for a very dangerous type of skin cancer

called merkel cell carcinoma(please see my previous articles on merkel cell carcinoma),a six fold

increase for basal cell carcinoma and a two fold increased risk for melanoma.

Please see my previous article entitled: Skin Cancer-not just from the sun.

           In addition, the prevalence of skin cancers is also high among individuals infected witrh

HIV (human immunodeficiency virus) and lesions in this population tend to be more aggressive.

Also,  there is a high risk of squamous cell carcinoma  associated with seropositivity  for the

human papilloma virus (HPV)  type 16 and 18 but a direct causal relationship has not been

established.

           Individuals with a history of skin cancer are at increased risk for another skin cancer and

people living in areas where the sun's rays are most intense such as the equator have an

increased risk for melanoma skin cancer.

          I saw a new patient in my office this week who came in for another problem but complied

with my request to take his shirt off when I promptly diagnosed a melanoma on his back.

         A few years ago I diagnosedf 6  patients with  melanomas in about 6 months.

        In conclusion, if you see a change in the size,shape,color or behavior of spots on your

skin,get checked by your healthcare provider.

                                 Dermatologists and other health care practitioners are often visited by a patient with a

hand rash-sometimes accompanied by a foot rash also.

                                And,specialists like dermatologists often immmediately think of eczema,psoriasis,contact

dermatitis and, perhaps,even  a fungal infection.

                              As for myself,,in addition to taking a histoery of the rash  which includes how long he or she

has been aware of it,I also list any treatments already tried and I always ask the patient what he or she thinks

may have caused it.

                             In addition,I would immediately look at the patient's fingernails and elbows,looking for signs

of psoriasis which can be manifested by a red scaley plaque like surface on the elbows and ragged fingernails.

And,often I can make the diagnosis by the simple history and physical exam described above,especially if the

feet are also involved.

                           Also, a simple test for fungus not only includes taking a skin scraping for examination under

the microscope and /or a culture to try to grow it. In addition,a fungal rash is more likely to involve 2 hands

and 1 foot or 2 feet and 1 hand-thus,adding up to 3 rather than 2 hands and/or  2 feet .

                          However, the main thrust of this narrative is to impress upon the reader that there are many

more serious causes of hand and foot rashes than the above.

                         To begin with, Woringer Kolopp disease which is a cutaneous form of an internal cancer

called lymphoma is manifested by psoriasis like thickened plaques on the hands and also the feet. It is

a type of mycoses fungoides lymphoma which can be treated by surgical excision and radiation therapy

and could easily be mistaken clinically for psoriasis.

                        Another serious disease that can appear as a rash on the hands and feet is palmoplantar

syphilis which  could be misdiagnosed as palmoplantar psoriasis. In fact, secondary syphilis has often been

called one of the great  masqueraders in dermatology since it can mimic many types of skin didease and

is often missed when it can frequently diagnosed with a simple blood test.

                       Basex syndrome is a paraneoplastic(a set of signs and symptoms that is a consequence of

cancer in the body but is not due to the local presence of cancer cells)syndrome characterized by thickened

skin on the hands or feet(ie,acral areas) as well as on the ears and nose . It is associated with malignancies

of the upper aero digestive tract such as cancer of the esophagus.

                     And, I would not want to leave this topic by not discussing the entity known as "mechanic's

hands." Mechanics hands refers to a non-itching, thickened skin eruption accompanied by scaling,fissuring and

hyperpigmentation giving one the  appearance of the calloused hands of a manual laborer.

                   In my opinion,mechanics hands could be easily misdiagnosed as hand eczema. However,

over the years mechanics hands have become recognized as a clinical marker  for pulmonary disease

as well as occurring in a condition called Dermatomyositis . People with the latter have not only skin

rashes but a 20 % incidence of internal cancer.

                  Dermatomyositis is also characterized by muscle weakness,various other skin findings as

well as a marked sensitivity to the sun.,

                 In summary, I would urge patients with  dry thickened  skin on their hands(and feet) that has

not responded to topical and (sometimes)internal steroids  or  antifungals  to see their healthcare

provder  for a detailed history and physical exam of the entire body looking for telltale signs of internal

malignancy.

                    Coming soon.