Many systemic illnesses have distinct dermatological associations. Some of these are listed below:

Addison’s disease is characterized by pigmentation and vitiligo.

Cushing’s disease is associated with pigmentation, striae, hirsutism, and acne.

Diabetes mellitus can cause necrobiosis lipoidica, which presents as shiny, yellowish plaques on the shin. It can also lead to xanthoma, a condition characterized by yellowish lipid deposits in the skin, and granuloma annulare, which manifests as palpable ring lesions on the hands, face, or feet.

Hyperlipidemia is linked to xanthoma and xanthomata, which are yellowish plaques on the eyelids.

Crohn’s disease is associated with erythema nodosum.

Ulcerative colitis can cause pyoderma gangrenosum and erythema nodosum.

Liver disease often presents with pruritus, spider naevi, and erythema.

Malignancy can lead to mycosis fungoides, a type of lymphoma that affects the skin. It is also associated with acanthosis nigricans, which is often seen in gastrointestinal malignancies.

Hypothyroidism is linked to alopecia, while thyrotoxicosis can cause both alopecia and pretibial myxedema.

Reperfusion after a frostbite injury can be extremely painful, so it is important to provide strong pain relief. If there are clear blisters, they should be opened and aloe vera should be applied every 6 hours. However, if there are blisters with blood, they should not be opened, but aloe vera can still be used topically. Taking 400 mg of ibuprofen orally, if there are no contraindications, can help reduce inflammation and improve the outcome of frostbite. Technetium-99m pertechnetate scintigraphy is the preferred method for assessing blood flow in the affected area. To treat frostbite, it is recommended to re-warm the affected areas by immersing them in warm water.

Further Reading:

Hypothermia is defined as a core temperature below 35ºC and can be graded as mild, moderate, severe, or profound based on the core temperature. When the core temperature drops, the basal metabolic rate decreases and cell signaling between neurons decreases, leading to reduced tissue perfusion. This can result in decreased myocardial contractility, vasoconstriction, ventilation-perfusion mismatch, and increased blood viscosity. Symptoms of hypothermia progress as the core temperature drops, starting with compensatory increases in heart rate and shivering, and eventually leading to bradyarrhythmias, prolonged PR, QRS, and QT intervals, and cardiac arrest.

In the management of hypothermic cardiac arrest, ALS should be initiated with some modifications. The pulse check during CPR should be prolonged to 1 minute due to difficulty in obtaining a pulse. Rewarming the patient is important, and mechanical ventilation may be necessary due to stiffness of the chest wall. Drug metabolism is slowed in hypothermic patients, so dosing of drugs should be adjusted or withheld. Electrolyte disturbances are common in hypothermic patients and should be corrected.

Frostbite refers to a freezing injury to human tissue and occurs when tissue temperature drops below 0ºC. It can be classified as superficial or deep, with superficial frostbite affecting the skin and subcutaneous tissues, and deep frostbite affecting bones, joints, and tendons. Frostbite can be classified from 1st to 4th degree based on the severity of the injury. Risk factors for frostbite include environmental factors such as cold weather exposure and medical factors such as peripheral vascular disease and diabetes.

Signs and symptoms of frostbite include skin changes, cold sensation or firmness to the affected area, stinging, burning, or numbness, clumsiness of the affected extremity, and excessive sweating, hyperemia, and tissue gangrene. Frostbite is diagnosed clinically and imaging may be used in some cases to assess perfusion or visualize occluded vessels. Management involves moving the patient to a warm environment, removing wet clothing, and rapidly rewarming the affected tissue. Analgesia should be given as reperfusion is painful, and blisters should be de-roofed and aloe vera applied. Compartment syndrome is a risk and should be monitored for. Severe cases may require surgical debridement of amputation.

Shingles is caused by the varicella-zoster virus (VZV), which primarily infects individuals during childhood as chickenpox. However, the initial infection can also be subclinical. After the primary infection, the virus remains dormant in the sensory nervous system, specifically in the geniculate, trigeminal, or dorsal root ganglia.

During the dormant phase, the virus is kept under control by the immune system for many years. However, it can later become active and cause a flare-up in a specific dermatomal segment. This reactivation occurs when the virus travels down the affected nerve over a period of 3 to 5 days, leading to inflammation within and around the nerve. The decline in cell-mediated immunity is believed to trigger the virus’s reactivation.

Several factors can trigger the reactivation of the varicella-zoster virus, including advancing age (with most patients being older than 50), immunosuppressive illnesses, physical trauma, and psychological stress. In immunocompetent patients, the most common site of reactivation is the thoracic nerves, followed by the ophthalmic division of the trigeminal nerve.

Diagnosing shingles can usually be done based on the patient’s history and clinical examination alone, as it has a distinct history and appearance. While various techniques can be used to detect the virus or antibodies, they are often unnecessary. Microscopy and culture tests using scrapings and smears typically yield negative results.

Systemic lupus erythematosus (SLE) is a connective tissue disorder that affects multiple systems in the body. It is characterized by skin rashes, joint pain, and the presence of antibodies against double-stranded DNA. SLE is more commonly seen in young women, with a ratio of 10 females to 1 male. It is also more prevalent in West Indian populations.

One of the classic signs of SLE is the presence of a butterfly rash. This rash appears as redness over the bridge of the nose and cheeks. It is often worsened by exposure to sunlight and can occur before other symptoms of SLE develop.

Joint involvement is common in SLE and can affect both large and small joints. The knee, proximal interphalangeal, wrist, and metacarpophalangeal joints are most frequently affected.

Patients who have Eron class III or IV cellulitis should be hospitalized and treated with intravenous antibiotics. In this case, the patient is experiencing cellulitis along with symptoms of significant systemic distress, such as rapid heart rate and breathing. This places the patient in the Eron Class III category, which necessitates admission for intravenous antibiotic therapy.

Further Reading:

Cellulitis is an inflammation of the skin and subcutaneous tissues caused by an infection, usually by Streptococcus pyogenes or Staphylococcus aureus. It commonly occurs on the shins and is characterized by symptoms such as erythema, pain, swelling, and heat. In some cases, there may also be systemic symptoms like fever and malaise.

The NICE Clinical Knowledge Summaries recommend using the Eron classification to determine the appropriate management of cellulitis. Class I cellulitis refers to cases without signs of systemic toxicity or uncontrolled comorbidities. Class II cellulitis involves either systemic illness or the presence of a co-morbidity that may complicate or delay the resolution of the infection. Class III cellulitis is characterized by significant systemic upset or limb-threatening infection due to vascular compromise. Class IV cellulitis involves sepsis syndrome or a severe life-threatening infection like necrotizing fasciitis.

According to the guidelines, patients with Eron Class III or Class IV cellulitis should be admitted for intravenous antibiotics. This also applies to patients with severe or rapidly deteriorating cellulitis, very young or frail individuals, immunocompromised patients, those with significant lymphedema, and those with facial or periorbital cellulitis (unless very mild). Patients with Eron Class II cellulitis may not require admission if the necessary facilities and expertise are available in the community to administer intravenous antibiotics and monitor the patient.

The recommended first-line treatment for mild to moderate cellulitis is flucloxacillin. For patients allergic to penicillin, clarithromycin or clindamycin is recommended. In cases where patients have failed to respond to flucloxacillin, local protocols may suggest the use of oral clindamycin. Severe cellulitis should be treated with intravenous benzylpenicillin and flucloxacillin.

Overall, the management of cellulitis depends on the severity of the infection and the presence of any systemic symptoms or complications. Prompt treatment with appropriate antibiotics is crucial to prevent further complications and promote healing.

The primary cause of roseola is the human herpesvirus 6B (HHV6B), with the human herpesvirus 7 (HHV7) being a less common cause.

Further Reading:

Roseola infantum, also known as roseola, exanthem subitum, or sixth disease, is a common disease that affects infants. It is primarily caused by the human herpesvirus 6B (HHV6B) and less commonly by human herpesvirus 7 (HHV7). Many cases of roseola are asymptomatic, and the disease is typically spread through saliva from an asymptomatic infected individual. The incubation period for roseola is around 10 days.

Roseola is most commonly seen in children between 6 months and 3 years of age, and studies have shown that as many as 85% of children will have had roseola by the age of 1 year. The clinical features of roseola include a high fever lasting for 2-5 days, accompanied by upper respiratory tract infection (URTI) signs such as rhinorrhea, sinus congestion, sore throat, and cough. After the fever subsides, a maculopapular rash appears, characterized by rose-pink papules on the trunk that may spread to the extremities. The rash is non-itchy and painless and can last from a few hours to a few days. Around 2/3 of patients may also have erythematous papules, known as Nagayama spots, on the soft palate and uvula. Febrile convulsions occur in approximately 10-15% of cases, and diarrhea is commonly seen.

Management of roseola is usually conservative, with rest, maintaining adequate fluid intake, and taking paracetamol for fever being the main recommendations. The disease is typically mild and self-limiting. However, complications can arise from HHV6 infection, including febrile convulsions, aseptic meningitis, and hepatitis.

Methicillin-resistant Staphylococcus aureus (MRSA) has become a significant issue in hospitals and other healthcare facilities in recent years. MRSA refers to any strain of Staphylococcus aureus that has developed resistance to beta-lactam antibiotics, such as penicillins and cephalosporins. This resistance is caused by the presence of the mecA gene, which produces a penicillin-binding protein with low affinity. Fortunately, MRSA is typically susceptible to teicoplanin, vancomycin, daptomycin, and linezolid. On the other hand, imipenem is an intravenous beta-lactam antibiotic that belongs to the carbapenem subgroup.

Stevens-Johnson syndrome is a severe and potentially deadly form of erythema multiforme. It can be triggered by anything that causes erythema multiforme, but it is most commonly seen as a reaction to medication within 1-3 weeks of starting treatment. Initially, there may be symptoms like fever, fatigue, joint pain, and digestive issues, followed by the development of severe mucocutaneous lesions that are blistering and ulcerating.

Stevens-Johnson syndrome and toxic epidermal necrolysis are considered to be different stages of the same mucocutaneous disease, with toxic epidermal necrolysis being more severe. The extent of epidermal detachment is used to differentiate between the two. In Stevens-Johnson syndrome, less than 10% of the body surface area is affected by epidermal detachment, while in toxic epidermal necrolysis, it is greater than 30%. An overlap syndrome occurs when detachment affects between 10-30% of the body surface area.

Several drugs can potentially cause Stevens-Johnson syndrome and toxic epidermal necrolysis, including tetracyclines, penicillins, vancomycin, sulphonamides, NSAIDs, and barbiturates.

Onchocerciasis is a parasitic disease caused by the filarial nematode Onchocerca volvulus. It is transmitted through the bites of infected blackflies of Simulium species, which carry immature larval forms of the parasite from human to human.

In the human body, the larvae form nodules in the subcutaneous tissue, where they mature to adult worms. After mating, the female adult worm can release up to 1000 microfilariae a day.

Onchocerciasis is currently endemic in 30 African countries, Yemen, and a few isolated regions of South America. Approximately 37 million people worldwide are currently infected.

Symptoms start to occur around a year after the patient is infected. The earliest symptom is usually an intensely itchy rash. Various skin manifestations occur, including scattered, red, pruritic papules (acute papular onchodermatitis), larger, chronic, hyperpigmented papules (chronic papular onchodermatitis), lichenified, oedematous, hyperpigmented papules and plaques (lichenified onchodermatitis), areas of skin atrophy with loss of elasticity (‘Lizard skin’), and depigmented areas with a ‘leopard skin appearance, usually on shins.

Ocular involvement provides the common name associated with onchocerciasis, river blindness, and it can involve any part of the eye. Almost a million people worldwide have at least a partial degree of vision loss caused by onchocerciasis. Initially, there may be intense watering, foreign body sensation, and photophobia. This can progress to conjunctivitis, iridocyclitis, and chorioretinitis. Secondary glaucoma and optic atrophy may also occur.

In a number of countries, onchocerciasis has been controlled through spraying of blackfly breeding sites with insecticide. The drug ivermectin is the preferred treatment for onchocerciasis.

Eczema herpeticum occurs when an individual with atopic eczema comes into contact with the herpes simplex virus. While some patients may only experience typical cold sores, others may develop a more extensive infection. This condition is often accompanied by systemic disturbance and can be quite painful. Administering antiviral treatment can help reduce the duration of the illness. In cases where the rash is widespread or there are concerns about eye complications, hospital admission may be necessary for intravenous antiviral therapy.