Tuesday, 17 September 2013

Truncal eruptive vellus hair cysts



Eruptive vellus hair cysts (occlusion and cystic dilatation of vellus hair follicles) commonly present as asymptomatic small red, yellow, bluish-grey or brown, papules (occasionally scaly) on the chest, abdomen (A), and axillae (B) in the second decade of life. They were first reported in 1977. The diagnosis is often made clinically, because of typical age of onset (before puberty), the site of the lesions, and their appearance. Histopathologic examination reveals a cystic structure located in the middle or upper dermis. It is lined by a stratified squamous epithelium with focal features of outer root sheath differentiation at the level of the follicular isthmus and trichilemmal cornification. The lumen contains keratin and numerous transversely and obliquely sectioned vellus hair shafts. Some cysts may show a connecting pore at the skin surface, the likely mechanism of the spontaneous regression. Also, incision or puncture of the cyst and examination of the contents in potassium hydroxide, under a microscope will reveal the vellus hairs. Eruptive vellus hair cysts can overlap clinically and pathologically with steatocystoma multiplex (hybrid cysts). The so-called steatocystoma multiplex suppurativa mimics acne conglobata. Twenty-five percent of eruptive vellus hair cysts cases spontaneously regress through transepidermal elimination. Various methods have been used to treat the lesions but beware of scarring. The lesions may clear after application of topical retinoids. Erbium: YAG laser has been successful in treating the lesions*. 



A

B


*Kageyama N, Tope WD. Treatment of multiple eruptive hair cysts with erbium : YAG laser. Dermatol Surg 1999; 25: 819–22.


This page was last updated in April 2014






Friday, 13 September 2013

Oral antiretroviral pre-sexual exposure HIV prophylaxis, causes for concern



Sexual contact is the most common route of HIV transmission* whose rate of infection after a sexual contact varies according to the nature of the contact and whether it is protected or not and the HIV subtype. The search for potential vaccines has yielded little result. Oral antiretrovirals, life saving drugs for HIV-infected patients, have a role to play among other means in the prevention of sexually transmitted HIV infection in at-risk HIV negative populations. In this context, they are used for pre-sexual exposure prophylaxis (PrSEP), post-sexual exposure prophylaxis and early treatment of the HIV-infected partners. Other means include topical antiretrovirals, male circumcision and male/female condoms. Certainly abstinence is the definitive way for prevention of any sexually transmitted infection. Pre-exposure prophylaxis that is shown to be effective in reducing HIV transmission in one population may not necessarily work in other at-risk populations, hence the conduction of trials in different population groups representing different routes of HIV transmission, including heterosexuals, MSM, and injecting drug abusers.

The concept of providing pre-exposure prophylaxis is not new. Apart from vaccines, a famous example is the pre-exposure prophylaxis against malaria for travellers to endemic areas. Theoretically, if HIV replication is inhibited from the moment the virus enters the body, it may not be able to establish a permanent infectionPrSEP has been shown to reduce the risk of HIV infection among adult men and women at high risk for HIV infection through sex.  The FDA has approved the combination medication tenofovir disoproxil fumarate plus emtricitabine for use as PrSEP among sexually active adults at risk for HIV infection. At-risk populations such as MSM are not necessarily aware of the presence of PrSEP. However, knowledge about this role of oral antiretrovirals may have effect on willingness to accept it. Serodiscordant couples have been advised of early treatment for the infected partner, PrSEP for the uninfected partner, or a combination of the two. PrSEP might be an effective prevention method for women who are unable, for whatever reason, to negotiate condom use. PrSEP might also be used as a risk reduction strategy for HIV negative women who request to conceive naturally from HIV positive men via timed unprotected sex, PrSEP for conception (PrSEP-C). 


It should be noted however that PrSEP can give a false sense of security that might lead to easier transmission of other sexually transmitted infections.  Moreover, continued use of a PrSEP regimen in the presence of undiagnosed HIV infection is analogous to the HIV monotherapy or dual therapy strategies used in the early stages of the HIV epidemic. Such regimens are known to carry an unacceptably high risk of HIV drug resistance, with important clinical implications for the patient and public health implications for the sexual partners. Extensive studies are needed to address the safety concerns associated with use of daily oral PrSEP in HIV negative people, whether in long or short term courses, and to address cost concerns of PrSEP and feasibility to deliver it.

*National statistics show injection drug use is the principal mode of HIV transmission in Iran.

This page was last updated in October 2013.

Monday, 9 September 2013

Papillon–Léfèvre syndrome




Papillon-Léfèvre syndrome is a very rare syndrome of autosomal recessive inheritance (the prevalence has been estimated as 1–4 in 1 million) characterised by palmoplantar keratoderma (A), and periodontitis (C). The lesions may extend to the dorsal hands and feet and may also be present on the elbowsknees (B), and Achilles tendon areas. The condition usually has an early age of onset. The severity of the periodontal disease does not correlate with the severity of the skin lesions. Periodontitis leads to the loss of deciduous teeth by the age of 5 years unless treated; permanent teeth may be lost in the same way. Associated hyperhidrosis causes an unpleasant odour. The hair is usually normal. Other associated features have been reported such as pyogenic infections of the skin and internal organs and pseudoainhum of the thumb.

This condition is caused by a mutation in the lysosomal protease cathepsin C gene located at chromosome 11q14.1–q14.3This explains the predisposition to pyogenic infection, but the mechanism of keratoderma is not established.   The phenotypically related Haim–Munk syndrome (it combines the features of Papillon–Léfèvre syndrome with onychogryphosis, arachnodactyly and acro-osteolysis) is an allelic mutation. There may be mild phenotypic expression of the disease with late onset and mild skin or periodontal disease. In some late-onset patients, no mutations in the cathepsin C gene were found, suggesting the possibility of another genetic cause. Periodontitis is also present in the ‘HOPP’ syndrome (hypotrichosis, acro-osteolysis, palmoplantar keratoderma, and periodontitis) but there is no mutation in the cathepsin C gene.


Histopathological changes are non-specific. Treatment with oral acitretin has been effective in controlling the disease. 


A
B
C
This child has presented with hyperkeratosis of the palms and soles that has first developed during the first few months of life. The lesions spread on the elbows and knees over the following years. On examination, loss of dentition has also been noted. It has started since the eruption of deciduous teeth. A diagnosis of Papillon-Léfèvre syndrome was made. Treatment with acitretin has been discussed with the mother and it was decided to postpone it in view of the possible side-effect of premature epiphyseal closure. The patient is currently being treated with topical preparations for symptomatic relief.




This page was last updated in September 2013.

Main Works of Reference List (The first eight are my top favourites)

  • British National Formulary
  • British National Formulary for Children
  • Guidelines (BAD - BASHH - BHIVA - Uroweb)
  • Oxford Handbook of Genitourinary Medicine, HIV, and Sexual Health
  • Oxford Handbook of Medical Dermatology
  • Rook's Textbook of Dermatology
  • Simple Skin Surgery
  • Weedon's Skin Pathology
  • A Concise Atlas of Dermatopathology (P Mckee)
  • Ackerman's Resolving Quandaries in Dermatology, Pathology and Dermatopathology
  • Andrews' Diseases of the Skin
  • Andrology (Nieschlag E FRCP, Behre M and Nieschlag S)
  • Bailey and Love's Short Practice of Surgery
  • Davidson's Essentials of Medicine
  • Davidson's Principles and Practice of Medicine
  • Fitzpatrick's Colour Atlas and Synopsis of Clinical Dermatology (Klaus Wolff FRCP and Richard Allen Johnson)
  • Fitzpatrick’s Dermatology in General Medicine
  • Ganong's Review of Medical Physiology
  • Gray's Anatomy
  • Hamilton Bailey's Demonstrations of Physical Signs in Clinical Surgery
  • Hutchison's Clinical Methods
  • Lever's Histopathology of the Skin
  • Lever's Histopathology of the Skin (Atlas and Synopsis)
  • Macleod's Clinical Examination
  • Martindale: The Complete Drug Reference
  • Oxford Handbook of Clinical Examination and Practical Skills
  • Oxford Textbook of Medicine
  • Practical Dermatopathology (R Rapini)
  • Sexually Transmitted Diseases (Holmes K et al)
  • Statistics in Clinical Practice (D Coggon FRCP)
  • Stockley's Drug Interactions
  • Treatment of Skin Disease: Comprehensive Therapeutic Strategies
  • Yen & Jaffe's Reproductive Endocrinology